A bad situation and hopefully some have learned a lesson.
Bottom line has been correctly posted before, if you borrowed the money, you owe the money. What you did with the money is irrelevant.
As it happens you purchased the truck with the money, separate issue.
the truck was wrecked, you have a wrecked truck. Inadequate insurance to pay for the damages is a lesson learned.
You may want to try and sue for the damages to the truck from negligence, problem is most courts limit small claims to $5k, check your county clerk and find out. Otherwise your going to civil court, attorneys, and related costs, probably cheaper to fix the truck on your own. Also, a judge may find issue with your claim in Small Claims court if you never discussed who was responsible for any damages to the truck should an accident happen while he was driving. From my experience with a car that was stolen from me and involved in a wreck, I was responsible for the repairs to my car, not the person who stole the vehicle.
It is a bad situation but not because of the actions of your friend, but from mutual initial trust involving a large amount of money.
IMO, you pay the money you owe, try small claims to recover what you can if you can get a judge to agree with you, learn from this and consider it what we call....."Stupid Tax". Believe me your not the first to learn this lesson.
Best of luck.