If the guy he hit has a permanent injury, then I wouldn't bat at an eye at any punishment handed out to this man. Slow torture. Castration. Do whatever you want to him. He's potentially ruined someone else's life, potentially affected more than just one person.
God, some of us are so stupid. Can't we just do away with them? Please?
Just for clarification, my post was a joke. While it's funny to laugh at other people being dipshits, if he hurt someone else seriously, that shit ain't cool.