They have every duty to keep him alive and healthy, up to the point of him expiring naturally.

Didn't they fail that when simple kidney stones evolved to a life threatening condition?

I'm not doctor, and I don't know the case, but it wouldn't be first time a "correctional" facility violated this duty.

It's not a far fetch argument to suggest that incarceration in US prisons is cruel -- I'm suspect history will look back at us with horror.