I hope my abusive uncle dies
Why do you think your uncle should die?
He's only in the hospital to die
That sounds hard. You don't have to wish the best for abusive people, but you should try not to focus on him or hatred for him. It will only hurt you in the long run.
I am not sure why my family keeps him alive.
Maybe you can discuss with your family the harm your uncle has caused you? It might help you deal with the trauma that seems to be impacting you.