I had a similar thing happen to me back in 1997.. Guy driving a newly restored old F-150 fell asleep at the wheel, and rammed my GMC Jimmy straight into a tree in my neighbor's yard. My alarm going off woke me up (it was 4:30am when it happened).
It was a royal PITA dealing with the guy's insurance company, but it eventually got worked out. My only problem was that the guy's insurance adjuster didn't come out for 2 days, and I couldn't get a rental until he showed up. Not a huge deal, since I had another car at the time, but was still an inconvenience. The part that sucked is that I had to FIGHT just to get a Corolla, they were trying to put me in a Ford Aspire! The whole ordeal took just over a month, and I drove the crap out of that Corolla in the meantime.
Your insurance company can help you figure things out, but his insurance company will be paying for everything so you'll ultimately be dealing with them. Good luck with everything.
