If the guy came back and pumped 5 more bullets into an unconscious kid, then he's not defensible. If the kid was still fucking with him, different story.
Self defense is different than being given carte blanche to kill anyone and everything once the situation is safe.
Grind. Stop it.
as I said, I don't agree with pumping the kid full of lead. However many of us have never been in that situation before. I cannot imagine with the adrenaline, the fight or flight kicking in your brain, the fear, the nerves, how rattled one is, you just loose cognition. chances are you don't act rationally. Temporary insanity if you will. This man did not bring this situation upon himself. I don't feel he is a future threat to society, and I don't think he deserves to be in jail.