I know this probably isn't the best place to ask for legal advice but it's Sunday and it's worth a shot....?

My boyfriend has a prior record although until now he hasn't been in trouble in a long time. He is a good person he has just made some bad choices. We live in Texas by the way. He had 2 warrants in the county we live in from about 4 years ago. Back in June he was driving his best friend's car and totaled it. He hit his head pretty hard (spiderwebbed the windshield) and he says he barely remembers anything from that week. After the wreck he hitched a ride back to the shop he worked at and asked a friend of his to borrow his car. The friend told him to take his girlfriend's car which wasn't as nice of a car. He even gave him details on what all was wrong with it and told him how to fix it if something went wrong. His friend didn't tell his girlfriend he let him borrow it. My boyfriend ended up disappearing for about 4 days and they reported the car stolen. He's already taken care of the previous warrants and now they are charging him with unauthorized use of a motor vehicle. He had permission the guy is just afraid his girlfriend will get mad at him. What can we do?