It may vary from insurance company to insurance company, but, in general, when you exclude someone from driving, your policy's insurance coverages are not extended to that person if that person drives. Now, the coverages usually extend to the person if that person is a passenger in your vehicles. You should contact you insurance company to make sure your current understanding is correct. Now, if your son is a passenger in someone else's vehicle, the owner of the other vehicle may have coverages that will cover your son like Personal Injury Protection and Uninsured Motorist.