What To Do???

My 26 year old son, 25 at time of accident, moved about 15 minutes from his mom and they forgot to notify the auto insurance company of the move. He got into an accident in which he was at fault. Insurance company is denying the claim citing a failure to report his change of address. They did cut him a check for premiums he paid from the time of the move to the time of the accident but will not pay the cost of the accident. Does he have any recourse given the move was only 15 minutes away?