Sad for his children but if he had had enough and didn't want to live the rest of his life in a deteriorating state who is anyone to judge?
Recently had to watch my nan go out due to dementia, a sorry state by the time she died. My dad said he'd like to end it before he got like that, reliant on others and a burden, i think he's right. My nan if she could have come out of herself would have felt the same.