I am not saying he should go to prison for life, but when do we actually enforce consequences to people who at 18 like it or not is an adult and did something even a 5-year-old would know isn't right and ended up seriously hurting someone.

Reality is there are consequences and yes it might suck for this kid, but he has to pay them. At this time, it is up to the law and probably the person injured to say what those might be.