Many that live deserve death. And some that die deserve life. Can you give it to them? Then do not be too eager to deal out death in judgement. For even the very wise cannot see all ends. I have not much hope that Gollum can be cured before he dies, but there is a chance of it.
This sob deserves death by torture. Look at the raw destruction he is willing without threat to put on another human for the rest of their life.