actually i think the most accurate legal thing they ever showed was the concept of the plea bargain w/chris hobbes. i know from experience that money, the right lawyer, (which takes connections and money) and a few other string pulling type manuevers can get you out of a shitload of trouble in PA.
so i believe that if the did get it down to simple assault, that he could have gotten off with community service and a fine. If he was under 18 it would be on his sealed record and would never affect his adult life unless he wanted to work for the FBI. but i'm not a lawyer, and i'm really just quoting the show, in which Brian says (in season four) that the law has already shown that they don't give a shit.