That is exactly the wrong attitude. It IS a big deal. He easily could have killed himself and others. It was dangerous, reckless, and stupid. If he had hit another car he would have gone to jail, and if someone had died could easily have been convicted for involuntary manslaughter. Just because you don't hit anyone with a bullet doesn't make firing a loaded gun into a crowd "not a big deal."
I get it- we have all been there before. We all speed, we all do dumb things when we are 20. I did something similar to Tyreke's incident when I was about his age. It is part of being young, but you have to learn from it.
Having people tell him "it is no big deal" is no help. He needs people to tell him "you freaking moron, why the hell would you do that. Just because you are young, rich, and the face of the city doesn't make you immune to things like this." He needs to be embarrassed and ashamed. That is how you learn from something like this. If everyone says it is no big deal, he will think he can do it again.
He is a good kid, and I think has the right frame of mind to learn from this. He also got lucky as hell that something more didn't come of this. maybe my perspective is different as a parent, but I would go through four stages on hearing this news: 1) thank god he is alright, 2) thank god he didn't hurt anyone else, 3) hope that he is not so stupid again, and 4) dress him down as much as possible to damn well make sure it doesn't happen again. I certainly would not tell him it is "no big deal..."