It has been mentioned, but she won't have that either.You could always invite her to come and live with you, so you can look after her.
Maybe, she will go suddenly like her 95 YO mother (who she nursed) who cried out at 6AM "Ohhh Dotty I feel sick" and then just went out like a light with a mahoosive stroke.
No suffering, a pampered life and no lingering painful end. Perfect!