There is no deductible on liability insurance, only on collision and comprehensive. He should definitely notify his insurance company and they'll pay. However, they won't pay for a new one.
Every state has a minimum claim threshold below which the insurance company can't increase rates as a result of the claim. In other words, for a claim this small, your neighbor has nothing to lose to notify the insurance company. You, on the other hand, will not get a 450 grille.
you should call Potomac German Auto for a good used one, they are on the web at
www.pgauto.com. I've gotten several fantastic parts from them. Try to speak with Pat.