Difficult sibling and caring for parent- boundaries without unnecessary upset?

My god, your brother sounds like bloody hard work. But then your mother has spent decades allowing him to be - positively encouraging him to be, in fact. I know she's old and frail now, but she's been training him to be a colossal pain in YOUR backside since she wasn't, right? She's really just reaping what she's sown.

You're right, you have to let it go wrong - not just that, but decline to pick up the pieces when it does. Oh, db can't clean at the moment? Three choices then, mum - wait until he starts cleaning again, get the cleaner back, or he can arrange a cleaner he's happy with. Up to you! Or up to him, if he's taken responsibility for cleaning - one way or another, he ensures it's done.

You must have the patience of a saint - I would have stopped talking to him years ago. Good luck.

OP, does your brother hope that by not spending money, your mother will give him some or is he Planning on an inheritance?
You could tell him that you are trying to get people in to save you mother going into a home and spending money on fees.

Sounds like you're doing really well - keep it up!

Can't you stop him interfering by just arranging the cleaner or whatever without mentioning it to him first? If he moans, ignore (or tell him he can either get over it, or do the cleaning himself). Same response to mum, if he persuades her to complain when there's nothing to complain about: "I'm not going to do your housework, so would you rather depend on DB, or leave it to Jane here?". If he's not paying, it's not his business - so don't respond to him as if it is. Stand firm!

If your mother can’t leave the house, do you need to tell her when you are coming?
As your mother has enabled your brother for most of his life, I wouldn’t feel too charitable towards your mother, in respect of avoiding arguments in front of her. I agree with the other posters about treating your brother with grey rock.
Surely if things get too bad for your mother then social services may be involved for assessment but you have to be prepared to let things fail.
While your brother may not be a nice person, you have chosen to help your mother, you cannot expect him to spend his time helping her.

Definitely don’t call him out, that will just cause drama and also he won’t change. For these type of people drama is actually a good result because it forces you to keep engaging, keep discussing, and they think then they can persuade you or wear you down.

this is why grey rock works well - no drama, no discussion, just “I’m not going to do that for you”, “I’m not available to do that for you”, “I’m sure he can do that for himself” and nothing else that he can argue with.

So don't call him out; just ignore him and don't do things for him. And if he whines to mummy, ignore that too (but in a gentler way; obviously don't be harsh with her, but be firm about not discussing it). Maybe asking her if she'd rather be left in his sole care would do the trick. A few weeks of just not reacting to him (or her, if he gets her to interfere) will probably cool his jets. He'll soon learn it's not working any more.

Your brother is lazy and manipulative and completely out of order to expect you to help him with childcare under the guise of helping your mum.

The 'throwing things about', even only occasionally is abusive. It's obvious that he is the golden child who can do no wrong, and your mum will do anything to avoid upsetting him, including trying to guilt trip you into helping him.

Keep an eye on his behaviour and report to Social Services if he crosses a line. Refuse to do anything to help him with his child. He has no right to expect this when you are doing so much for your mum, despite living so much further away, and he is just 'popping in' but doing nothing practical to help.

Keep on with the grey rocking and don't react to his tantrums. Come back to all of his requests with "Gosh, no, I'm far too busy for that - in fact I need you to do mum's shopping this week and take her to the doctor next week", or "Oh no, I'm swamped - in fact can you just come and do a tiny bit if DIY at my place?". He probably won't do what you ask, but it'll stop him asking you for stuff.

He's the one upsetting your mum, not you. Absolutely deliberately, because he knows that's the way to manipulate you. What a prick. So just draw a moratorium on discussing it with her at all - no exceptions. "Not discussing that mum. OK, Tuesday at ten for the doctor, be ready. Bye now".

We have slightly similar (although in my case my sister is pushy/manipulative/needy rather than aggressive).

I’ve found the grey rock technique really helpful, along with having a very clear and defined sense of what I am willing to do.

So any time he asks you say “I’m not going to do that.” If pushed for reasons or justifications, just say “I have my own life and priorities; I’m not available to help you with that”. Never give detailed explanations as he will argue or try to wear you down.

When he gets aggressive or bullying you say “Please don’t talk to me like that”, and when he continues you say “I’m ending the conversation and leaving now”. Never rise to it, but also never let him get away with it.

And with your mother just keep reiterating “I’m not going to do that for him. He can sort that out for himself”, again don’t enter into discussion about it. When she says she wants everybody to get along you can say “I think that’s unlikely while he’s constantly pressuring me to do things for him. We’d get on better if he accepted my answer is no”.

one thing I’ve found helpful is never talk about “helping out” or “errands” - those terms tend to sound normal, and like things a loving sister would do. Instead I always say “I won’t do that for her.” - it’s a subtle shift but constantly highlights that actually she just wants me to do stuff she doesn’t want to do for herself.

And if you’re worried about his behaviour around your mum call adult social services and flag her as a vulnerable adult.