What does insurance cover after a DUI?

My stepson has gotten 2 DUI's in 2 years. Before his license was suspended in NJ, he moved to PA and got a license. He now comes to our house in NJ often and borrows our cars. I think he should not be driving and it is illegal. Also, I think that if he gets in an accident here it wont be covered by our NJ insurance. My husband disagrees and says he has a legal license so all is fine. Please advise.