I so sorry but it sounds as if the daughter is in denial, relationships are complicated.
would it be possible to meet up with the daughter & give her one on one time with her mother - a reality check of the situation!
Also it would give you a chance to have a couple of hours break. X
She goes from panicking about her mum's health to denial and back again. There was even a lunch time conversation towards the end of last year when she was animated about her mum's treatment in hospital 15 years ago and suddenly started talking about something totally different in mid sentence. She did come round when I was away for a couple of days last summer, but then she phoned me to complain I had sent a couple of jumpers to the charity shop I already said were not needed and we had no space for. She does not seem to realise her mum stays in the house 5 days a week and while C likes new jumpers she can't wear them all and once and we live in a small flat with nowhere to store the ones she never has a chance to wear.
There was also a wet windy day a few years ago when she shouted at me for dropping an umbrella in the middle of pizza express while trying to get C into a seat while she sat and did nothing. The umbrella was hung up by me when I got a chance and the place was empty. I had thought she was becoming more supportive, but the incident with the chair yesterday just made me think she is so full of her own thoughts she is not interested in helping out.
Sorry I went off on a bit of a rant again, it's just been years of up and down domineering behaviour which I finally got fed up taking from my brother and my mother years ago.