[mfanatic325]

Interesting on the headrest feature; didn't know about those. As for the fault on dash, I would get that looked at just for future peace of mind. Try to get the kid's insurance to cover the diagnosis of that as well as the bodywork for the damages.
I'm assuming someone was in your passenger seat at the time of the accident? If so, then the fault is probably from the belt receptacle tensioner, which is supposed to pull down on the seatbelt and hold a person in the seat firmly (not allow the upper torso to lean forward as much). Perhaps the tensioner just failed to operate correctly, or maybe because the accident wasn't too bad, so it tripped itself out. My guess is that to help the car owner save a bit of money, if the passengers aren't tripped, then the other safety features don't execute either. When I swapped my stock driver seat out for a bucket seat for the track, I transferred the seatbelt tensioner along with the seatbelt receptacle; which is why I can comment on this with my hunch. The tensioner seems to be actuated via a hydraulic cylinder, perhaps with compressed gas or something; and I think it would be one-time use if activated. Would need to replace that cylinder, and I'm betting it's not cheap lol...
In any case, like I said, I would get it looked at just to be safe. Would want it fully functional in case of any potential future emergencies (ya never know!). G'luck.