To be honest. No way.

I wouldn't lend my GF, same age as me, my van for a long distance
trip. I certainly wouldn't lend my kid one unless he/she had proven
he/she could maintain and fix one on the road. You won't sleep well.
By 20 I had rebuilt a Triumph Spitfire, a Fiat 124 Sport Coupe, and
many hours working with my dad on various family cars into the wee
hours of freezing Maryland mornings. And I still would not have felt
comfortable borrowing his car for a trip like that. I had no problem
driving the Fiat from Maryland to Chanute Illinois where I was
stationed but then again it was my car and I had already discovered
all the secrets to keeping a Fiat on the road.

If he has a bunch of buddies going with him, let them rent a car.
Their responsibility, their money, their acceptance of being a young
responsible adult.

Or, let them use it and write it off. If it comes back unscathed, you
are ahead of the game. But don't expect it.

tim in san jose