Whoa! Your mum doesn't have access to her own money? I see trouble aheadThanks, yes the gp is aware. I can certainly ask the gp if they would do a home visit (don't think they are atm due to covid). My house isn't suitable to bring her here (fall risk and other mobility issues), so I would have to find a suitable respite place. The next issue would be how she would pay for that respite as she doesn't have access to her own money, everything goes via him.
It sounds like your dad has been very controlling for a long time - your poor mum. At some point you are going to need access to their money, to pay for care, and I can see your father is never going to agree to you having Power of Attorney. This will make things extremely difficult as you say he still has capacity.
Somehow you're going to have to prove that he hasn't - i.e. he is acting unreasonably. This is really, really hard to do. I think the only way forward (to save your poor mum) is to somehow get him sectioned. As your dad is getting very angry and aggressive when asked to discuss care/money, the only way I can think of is to get a professional to go there with you (GP, social services person, police officer) and have that conversation, insisting he must allow your mum to have a proper break and pay for it, plus carers for himself while she is away. Point out that half of the money is hers and he must allow her access to her funds. Say you are not leaving till this is sorted out. I'm assuming he will kick off in a big way which should prove to the professional who accompanies you that he does NOT have capacity and is putting your mother at risk as well as himself. With a bit of luck he will be sectioned...
Sorry if all this sounds a bit drastic but you've tried all the reasonable ways to get him to agree. They both need help urgently.