A convicted felon was told by the fire department to get into a car that had a gun in it - is he screwed?

A group of young men were told by firemen to go back up to the camp site to clean it up... following orders, they all got into the car. Once inside the car the police showed up, questioned the men and arrested my friend. It was not my friends car, and the guns weren't his either - all of the guns were licensed and the owners said they were only giving him a ride back up to the camp site. What chance does he have to get this thrown out...?