Advice for future-proofing MIL

It sounds to me like the biggest problem might be the house. Is it somewhere that could be adapted to ground-floor living if necessary, or is it completely unsuitable for wheelchairs/limited mobility? And how bad is the 'high maintenance' - is it just of the level of ''needs a lick of paint and a lot of cleaning, or more 'leaking roof, windows that won't shut, and a boiler installed in 1973'?

Is there anywhere in the village that might be suitable for her to downsize to in due course, or are you going to have to wait for things to become impossible then move her to a care home nearer to you?

Do you think she would accept carer visits when they become necessary, or is she going to insist on her independence, ie that you and DH do everything for her?

@PerformativeBewilderment there is an excellent group on here called the cockroach cafe....its for people who are dealing with elderly relatives and all the associated problems.
As @exexpat said how bad is the house??
This will be the main stumbling block and how accepting your mil is for having help.

I'm about 6 years ahead of you.

The technology issue is the most annoying, but the post office still accepts debit card payment for bills.
I tried to get her to set up direct debits, but that was frowned at.
I have to investigate and look things up for her online but generally it's fine.

Well, you said she has definite signs of cognitive decline. Along with the other issues you mentioned, it seems like it is time for changes.

I would first gather info. from people who are knowledgeable about the details of what an appropriate setting would be for her at this point, what's available in your area, the costs, and getting her to comply. Then you'll be ready to make a solid plan. I hope it goes smoothly.

You can speak to her GP if you're worried.
I just filled out the form online and they set up an appointment to discuss.

I have noticed that nothing seems to be linked, so the hospital tells the GP stuff, but doesn't seem to then say 'you should check everything is ok in 3 months'.
And the hospital says, contact the council about falls prevention, which you do, but it's a black hole, who can't see her notes and don't answer the phone

My advice would be to start ‘networking’ with the community, her friends, neighbours. You’ll need support and people on the ground to report back when things go downhill.

Can you join any local Facebook groups then use these as a good way to learn about other services that might be helpful? Also line up handymen and trades this way via recommendations.

I’m afraid I would bite the bullet re taking on the finances, because so much depends on how much cash she has. I don’t blame your Dh for not wanting to do it, but contacting the bank and getting set up with whatever they will offer (ideally full access and a PoA debit card) means that he can manage things at a distance and set things up tbh to be as convenient for him as possible. The sooner he finds out whether she can actually afford the life she has, and what kinds of resources she has for the future, the better. She may not be a fan of online banking but I doubt she would actually prevent your Dh from setting it up (if I’m honest I set up my own online access without telling my mum, even though she had capacity then - the things she wanted me to do were infinitely easier online and I was not going to spend every Saturday morning queuing up at the bank for her, even if the bank branch itself were still available.)

If she has any random little bank accounts and shareholdings, start getting those rationalised into fewer accounts asap, it takes FOREVER.

As far as the practicalities of where she is living, I would say don’t panic. TBH very little is selling right now so downsizing is much less accessible anyway. It is amazing what people will put up with to stay at home - sleeping on a chair, strip wash at the sink etc etc. The importance of familiar local routines and contacts becomes exponentially greater with cognitive decline.

Could have written a lot of this myself - my DM is wilfully helpless and expects men to sort out her life for her in DF’s absence. The main issue with mine is that she simply doesn’t see it as her responsibility and that people are being mean if they don’t do everything for her. All her friends’ husbands avoid her like the plague as she shamelessly presents lists of jobs she needs doing from tech-related to DIY, investment advice to calling utility companies. She just refuses to do things for herself. My advice is don’t do everything - it’s a slippery slope. Make her retain some level of responsibility. I really wish I had. DM just bleats and cries if she has to do life admin of her own now, even things she’s arguably totally capable of.

Make sure she gets her steps in every day and talks to people. Being at home too often can lead to loss of mobility and confidence quite quickly and the more human interaction she can muster, the better.
DH having POA is vital, even if you don’t need it for a decade.
I’d echo what PP have said about rationalising finances and getting your DH to maybe be a signatory on her current a/c or be able to do internet banking on her behalf. Yes it’s a chore but believe me it’s a million times worse if your DM loses capacity and you have no means to assist in the paying of her bills.
The big house needs careful thought - Selling houses is so brutal right now. I’d brainstorm all the options for her house and try to work
out the least worse options . Maybe be aware of the rental market for a little one bed near her or near you.
Keysafe for her house should also be on your list.
Hats off to you getting on the front foot now.

Her wanting the finances taken over is a huge plus. Yes, it's a pain to do - but being able to audit and rationalise it all now is far easier than having to plunge into a total mess in a few years time when she doesn't have capacity to answer questions about it.

Unlike the finance one, the health LPA only takes effect after she loses capacity. Before then you can give information to GP, social services etc; but unless she gives them permission they won't give you any info in response (whether they act on info you give them is variable).

If possible, get her to make an advance decision/statement of wishes about what health care she does or doesn't want in various circumstances. DNAs only cover cardiopulmonary resuscitation, there are a lot of less drastic treatments she may have views on. There are templates online that can take you through the various If-Thens.

Start researching care homes, extra care housing etc in her area and yours (and think about whether near you or near any existig social network she has would be best). She may not need it, and places do change so if she does need to move into one you'll always need to do some last minute work to confirm decisions, but it helps to have at least a longlist rather than starting from scratch if there's an emergency.

@PerformativeBewilderment one easy one. Get her registered on the priorities services registers for her utilities.

DM has an alarm with a button she wears round her neck. It’s been a godsend as she can contact someone if she falls.

Is she aware of her cognitive decline? I know most people aren't but my DM was, and was willing to go with me to speak to her GP to arrange a proper assessment. If she might do that I would encourage it sooner rather than later as (assuming you're in England) there is quite a long waiting list once referred for full assessment.

Regardless, would she be willing to give her GP permission to share information with DH? DM's GP had a simple form for this, and having it completed before we absolutely 'needed' it was very helpful.
At this stage I would advise you to think very carefully about what support network she already has locally and what additional support (eg community groups, paid carers etc) would be available if needed. Could she be persuaded to socialise a bit more outside her home? My DM was in a similar position. She didn't drink much but for years her social life revolved around friends and family visiting her. The number and frequency of visitors reduced over time as most of her old friends have either passed away or have mobility issues themselves. Younger family members are busy with work etc. I think a lot of older people over-estimate what support is actually possible from their remaining friends/family and under-estimate how much help they will need to remain 'independent' in their own homes.
Particularly if there is cognitive decline, be mindful of falling in to the trap of constantly 'solving yesterday's problem'. With any significant change (eg to accommodation, significant adaptions to bathrooms etc) consider how your mum will cope with them 6/12/24 months down the line.
Probably most importantly, protect your own mental health. Be wary of taking on any tasks that you are not willing to do indefinitely, and outsource anything possible. It's quite common to end up doing a lot to get through a crisis, or 'just until we get things sorted out' and then this becomes the expectation. If you can, try to have a sensible discussion with her whilst she is still managing alone about what she might want and what you could offer if/when she needs more help.