In fact, he should have been hung a long time ago.
Since other corruption in what is now laughably called a justice system makes this publicly unacceptable, we have the worst of both worlds. Maybe we will end up with the Swedish solution: 20 years in IKEA for mass murders.
Irrespective of the sentence he should have gotten then, I’m not sure it would even be a good idea to release somebody who’s spent 50 years away from society, having not had to function independently before that. He’d have no idea how to function on the outside.
Blazing Saddles comes to mind.