Should I back away?

My ex-husband who I’m still friends with, is very sick and has been in the hospital for six weeks. He will never walk again and he will have to be placed in a long-term care. We have been divorced for many years and I have still kept in touch with him. He doesn’t have anyone but me and his sister to assist him, he does have two daughters but they are useless. Should I continue to be his friend and help his sister during his illness and placement or should I back out of this since I am his ex-wife? He is only 63 years old. I don’t want to be his care taker. I want to live my own life.