i lived with my gran and grandad - he was blind, gran took a stroke it was a bad one and we knew she was not going to come home, i took him to see her and after 5 min he said, no point in being here, she is no use to me know, she died and i stayed but he was a horrid man, after 6 months i had to leave for my own sanity, i was 18, i could not take the verbal abuse and sometimes physical and the throwing things at me, he had not left the house since the 70s when he retired until he visted my gran in hospital, he never went to her funeral. i know this is not the same thing but sometimes you just need to do what is best for you, maybe a few weeks of not seeing you might make her realise how much you do for her, if you drive her about...tell her the car is off the road, tell her you are unwell, i was heading for this problem last year when my mum lost her husband, i just refused to take on the role, i have other siblings but they don't want it either. please take a few weeks and rest up, can you afford a holiday, good luck