Nice move. And at least you'll get to go jeeping this way
Just please make sure he understands center of gravity, and the fact that a lifted Jeep is a tradeoff - it can go off road, but does not corner fast. Nor do they do well at high speed on the highway. If he's racing someone, even someone in a crappy sedan, he needs to let the other guy win.
I know I was pretty crazy with my first vehicle, but certain points my dad made did stay in my head. You don't want him spending his life regretting the girls who died in the back seat because he was showing off.
Sorry about the downer - I'm not usually much for safety - but I think it's worth bringing up...