Yeah, at this point they would probably just give him some pain meds and tell him to rest a few days since there isn't a whole lot else they can do about it.Concussions are serious business for long-term effects, especially if you get them repeatedly, but judging from my friend who was in wrasslin school's many, many concussions if it doesn't kill him soon I don't think it will.
I think people may be panicking a bit too much. If Jace was going to die it would have probably happened by now. The most Brianna Wu will get out of this is some attention whoring and a restraining order. Jace's biggest problem is whether his mother presses charges over the car.