Poor thing. I know the feeling. It's a not nice/phew/thank god it didn't happen to me kind of thing. Makes you feel guilty and relieved at the same time.
Offer to buy it back from him for an insanely low price. If he takes the bait, buy it back and strip it for parts. Some of those parts would probably work real good on your current ride...
If you take full settlement for the car, then they own it free and clear and can do what they please.
You can take a reduced settlement in exchange for keeping the wrecked car. If you rebuild it, you must apply for rebuilt/salvage title and follow those rules, otherwise you can part it out.
I'm gonna assume the guy had standard insurance on the car rather than agreed value, so most likely less than $1k to get it back. You could easily part a 5.0 for more.
I'm going to see what happens...if I could I will but just some stuff back I really don't have room for the whole car...plus it's a good 3 hrs away too...