Sister has said she won’t help with our mum

The local authority should be willing to assess her needs.

Your sister is perfectly entitled to not want to help be your mother's carer. However she doesn't get to force you to take on that role. It clearly isn't fair on either you or your mother currently and I really think that you do have to take a step back from being her carer.
I understand if you feel resentment towards your sister, feeling that you would be able to manage better or for longer if she was to share the caring burden. But she isn't going to. I wouldn't want to either.
I think you need to present it to her as a done deal - clearly your mother now needs full time residential care. Does your sister want to be involved in finding the place or is she happy for you to arrange it. There's no other alternative.
I hope that having a break from being carer I'm improves your health.

Spending money belonging to someone with dementia is abuse. It’s a safeguarding concern. Please report it as such.
Nobody can now be given LPA is has to be with the Office of Public Guardian when someone has capacity to register it.
You could apply to court of protection for deputyship and that might be granted but you’d need steering through the process.

Please contact local authority and ensure your mother’s needs are paramount in decisions- which your sister has no legal basis for making. Go to the adult help desk and talk to duty social worker or speak to your mothers GP. If care agency providing visits is funded you could also speak to the commissioning team.

Your sister using the debit card is committing a criminal offence.

It’s odd that as the main carer you don’t have control of the finances.
I would contact social services to get the ball moving on a care home. Your DS can’t be forced to help but nor can she force you to do everything alone. That is wildly unfair and any reasonable person would realise that. Don’t give way or allow any manipulation on this. Inform sister that you have told social services you are only able to do X and your mums needs are Y therefore she will need to go into a care home. Don’t allow your sister control to you. On the finances front, I’m not sure the legalities needed but age UK may be able to give some general advice.

Do what you think is best. If your sister disagrees then she can take over.

Time for you to save yourself here. Your mum needs to go into a home and you or you family need to tell your sister to take over her care if she doesn't want her mum in a home because you are no longer able to care for your mum.

Your sister really shouldn't be using your mother's cards etc without power of attorney if your mum doesn't have capacity. I'd suggest if your mum has any points where she does have capacity, you get her to set you up with PoA (as people with dementia can sometimes have capacity if they are in a lucid phase). If not you need to go down the court of protection route and probably get social services to assess.

Old age lasts such a long time now that it can be a very difficult thing for all involved. We've had a lot of pain around how best to keep people looked after in my family too. In the end, my relative became very violent which was a difficult way for things to finish for everybody.

Op how does your sister have control of the bank account?

We had a similar situation in our family only with one keen sibling and one reluctant sibling, agreeing thinking it’d be temporary support as their mum slowly declined. All to avoid going into a home which to be honest could provide the most appropriate level of nursing care. Six years later the DM is going strong and everyone’s lives, beyond the two daughters, are held ransom by caring for someone who sadly has no quality of life. In a way it’s better for your sister to decline help now so you can come to a solution rather than have what we have, which is one reluctant carer who will do the bare minimum in every sense.

Surely if no one has p.o.a. then neither of you can dictate where your mum lives. If she has capacity that is her decision. Does she want to move to a care home. Is she able to make decisions. Firstly I would ask g.p. for a formal capacity assessment. Without that you wont get very far. If she has capacity you can ask if she wants to hand over p.o.a. if she doesnt then that's a different scenario and you'll need to speak to court of protection or public guardian for advice. With her money you can air concerns to her bank and safeguarding team.

If your mother’s dementia is such that she does not know where she is then you are not helping her by allowing her to remain in her own home.
The burden of caring for her there is too much for you to deal with even with carers.
So move her to a care home.

If your sister is not helping then her opinion on the matter is not relevant.

I’m upset that despite me sharing with ds how ill I am, she can still happily walk away but still make demands on how dm is cared for.

She can't. She can try, but she has no right to do so if she's abdicating any responsibility in care. If care is completely down to you then it's your decision.

for you OP, horrible situation but your mum doesn't know where she is as you say so it would be better for her to have the greater care of a home. Your sister doesn't get to have it both ways.

My uncle was like this when DGM needed care, refused to do anything to help but wanted to dictate what happened. We told him once, very clearly, that if he wasn't helping he had no say in how we helped and then ignored any further attempts to interfere. Sounds simpler than it was because he did kick back and try to stop us doing what we and DGM needed but we stuck to it and there really wasn't anything he could do.

Best advice I can give you is let go of the guilt/obligation feelings with regard to your sister. Decisions about DM's care affect you and DM, not Dsis (because she chooses to absent herself) so you and DM are the only ones whose needs and feelings need to be considered. You will drown if you continue doing what she wants instead of what you need

I was in this situation but much earlier in the timeline than you are. Mum was still mobile but needed daily care and wasn't safe. I knew my sister would do nothing since she always does nothing but talk. So Mum went into a care home and I was able to visit when I wanted to, and just spend time with her instead of doing personal care. It's the best option for you, OP.

Your sister has no right to insist your DM doesn’t go in to a home and then leave you with all the responsibility of her care.
Push forward with the plan for residential care and ignore your sister.

I’m powerless to change things as a result of not wanting to upset my mum or sister

Your Mum doesn't know where she is ....and your sister isn't helping at all. You need to take care of yourself and put your mother in a care home. Best wishes to you xx

Yes OP, this situation isn’t sustainable. Time to face it. Do you have any support from your Mum’s GP, or social services? They might be able to advise on next steps.

Just seen the update about the money situation though. As others have said, you need social services to do an assessment (I'm surprised the carers who come in 4 times a day haven't prompted this tbh).

You can’t just get a power of attorney. Your DM needs to have mental capacity to sign it, if she hasn’t got this then unfortunately you can’t get one. You would have to apply to Court of Protection to become a deputy, which can take up to 6 months and is costly.

In theory a bank should freeze a bank account once they know the account holder has lost mental capacity unless there is a power of attorney/deputy in place.

OP I am sorry about your DM. I would get her reassessed and see if she fulfills the criteria for a nursing home. Does she own her house?

There is no obligation from your sister though - you say your mum was controlling etc. Maybe she simply doesn't feel that she should help a woman who wasn't nice to her for many years.

Your sister is a cheeky cow. She cannot insist that your DM is cared for at home and do absolutely nothing to help. If she is indeed spending even a couple of quid of DMs money on herself, it is theft.

You do not need to wear yourself out like this OP. Your DM needs round the clock care. Get it sorted. If your sister protests, tell her she’s welcome to move in with DM and do it all herself.

For heavens sake put a stop to it now. Tell your sister that you are no longer available to care for your mother. She has control of the bank account so she can sort out an alternative or do it herself. Give her name as the contact person to all the medical people involved with your mother, seeing as she has nominated herself to be your mother's financial spokesperson. And step back fully. I appreciate it will be difficult to walk away for now, but it will surely be the whopping kick up the arse you're bitch of a sister needs to realise that your mother needs more care than you can offer. She's unreal to think she can control the spending but not do a thing to help.

I think you need to see your mums bank statements ASAP. Do you know if your mum has any money in her accounts? Is in debt etc? I agree with other posters its time for your mum to go into a nursing home, as hard as that is. It is too much for you and your health is suffering. I believe that finances will need to be disclosed/involved unless you are self funding the care and this will mean your sister can no longer have this money to spend as she wishes.

Honestly the way you describe your mother's living conditions I'm shocked you didn't move her to full time nursing care sooner. She deserves more than you and 4 carer visits per day are able to provide. Nursing homes are not terrible institutions across the board and it's time we accepted they often provide the best possible solution for people who can no longer look after themselves. I also believe very firmly that some patients get a new lease of life and positively thrive in nursing homes. I saw this in my own uncle who seemed very happy indeed for the last 3 years of his life (in a home) before he died aged 91.

Your sister is being manipulative and domineering....she is continuing the 'work' of your mother, your mother did a number on you and now your sister has taken the reigns and is doing a number on you

You need to block her