That could be just a state ID card, I have both. An ID and a DL. He may not have gone to get his DL renewed when he got out of jail before...
Interesting to know if he had been added to the car insurance policy for his mother's car. I learned this awhile ago, you do have to list each adult in the household who has access to the car keys on the car insurance. Although, he was not living there, she did give him access to the car for use.
Car insurance will cover "incidental" use, like you loaned your car to someone, but not if they actually live in the house. That is considered more than "incidental" use. Had a big discussion on this with teen step son...and car insurance. It ended up that he had to be insured in our home, and his Mom's home, for car insurance. Seemed like paying double to me.