If the car that hit him is not reported stolen, I would think he could claim against the owner and he would have to acknowledge if he allowed somebody to drive it and be liable for the damages.
I would also ask your insurance company if your son has any recourse under uninsured motorist portion of his policy
Several years ago, a guy backed into my wife's car at a QT, they exchanged information and we both had Geico Insurance. We turn it in, the car gets fixed, we have to pay the deductible to get the car back. It was like $8K in damages. The other party refused to acknowledge the accident or reply to Geico's calls, emails and certified letters.
I contact QT, verify they can obtain the video footage of the accident but I am not allowed to view or have possession of it, only Geico can see it. Go back and forth with them for several months until they finally obtain the tape. Another 2 months pass, they state they do not have the technology to view the tape.
We then filed a complaint with the AZ Insurance commission and the very next day the contacted us asking to settle. It was later explained to us that the person who did this is now uninsurable, I forget what law it fell under but it was essentially insurance fraud.
I wish you luck, our situation took 14 months to get our $1k deductible back and expenses for obtaining tapes and evidence.
