I'm not ready to dismiss him as a terrible person. You and the attorney want to do that, but I'm a little more stubborn. I see that there is room for the kid to still be a good kid who did something very regrettable.
I'm a father of 6 kids. 4 of them are over the age og 18 and I saw a lot of stupid stuff from my oldest two sons when they were 18 and under. Those boys did some things that would likely cause some people to label them as awful and perhaps irredemable. Both of them have turned into sweet, loving parents in their 20s.
Harshly judging a kid as bad kid because of one stupid, dangerous thing he did while part of an angry mob is something I won't do.