Hi Betty. My deepest empathy with you. I think if your mum has been deemed as having full capacity then there is not a lot you can actually do. On the basis we ALL have the right to decide what we want. You cannot force people to do anything but you can choose what you do yourself.
I would make everyone and I mean everyone, Her GP, community nurses and social services aware of your concerns. Then explain to your mum that you have to step back and look after yourself and your own family in these exceptional times. Maybe once she realises you can't be her back up for the time being she will relent and let others take over?
I don't mean don't ensure she has food etc but sometimes you have to step back and be cruel to be kind. You can buy food and leave it on the doorstep but don't go in. It will may be the action she needs to realise she does need outside help?
Hard for you I know and I can only wish you the best
Have any of you got all electric cars? Pros and cons please.