First off, glad you and family are ok. Not so much about the VX. :(
Having gone through something VERY similar, you might be looking at a battle depending on how you and ins approaches it. Whoever the car belongs to can EASILY (and sounds like they already have) say the driver did not have permission to drive it. This will relieve the registered owner of fault, thus rendering their insurance untouchable. There are avenues to try to go after the driver, but chances are slim since his insurance can pull the we insure "THIS" car, not the one he was in.
I went through that for 3 years here after my accident, though matters were a bit more difficult since the drunk driver in the vehicle that hit me was DOA. In the end, I ended up taking the claim from my own insurance (State Farm). Sucked, but I also was not penalized for it.
Best of luck to ya.