Life Insurance advice for a pretty unique situation

I want a life insurance policy for my immediate family, which includes myself, one parent, one sibling, and one nibling. I'm financially responsible for 50%+ of all 4.

I'm a fully healthy adult. My parent is a senior who is in good health for her age. My sibling has pretty serious health complications. Dialysis, plus a very weak heart. And finally my nibling is in prison. So obviously these circumstances are going to be pretty difficult to insure. I'm just trying to figure out a way to protect my assets in case the worst happens.