It basically comes down to "at fault". If, and it sounds like he will be, the other driver is ticketed claimed to be "at fault" by the police investigation and report, he is liable for damages. Meaning, his insurance company. I know some states have "no fault" claims and have to use their own insurance for damages.
NJ was like this when I lived there, and it sucked.... especially when you have a car totaled by another driver, who is ticketed for running a stop sign. I had no car, was dropped by my insurance, and got knee surgery. Go figure.
Depending on how your state handles it, you simply need their other driver's insurance info so you can file a claim with them for your damages to be repaired. I don't think that will happen in this case though, since it it sounds like the car was not his and the owners claim he had no permission to be in it. THAT is where the suck comes in. You will probably have no choice but to file the claim on your own policy. Like someone stated in an earlier post, it is actually a good time to get some legal consultation. Again, it really comes down to how your state allows insurance to operate and an accident lawyer would know better than anyone.
Gary Noonan
'01 S/C VX / '18 Forester XT