Geistware,
That's a tough call. Some guys really don't mind doing that kind of thing. They enjoy getting new planes all the time, they don't mind spending the money, and they have fun with their variuos planes before they crater. If that's the case, I'd just let him go (and hide under something solid when he's flying)

But, if he seems frustrated or annoyed when he crashes, you might offer to take him up on your (or someone else's) trainer for a flight after his next crash. Kind of a "Gee, sorry you lost your XXX, the weather's too nice to go home this early, want to get a little stick time on this trainer? It's better than nothing?" If that works, you can see if he can be convinced to pick up one of his own, espcially since money isn't the problem.