Another woman asked the same thing awhile back but I can't find the post. There is nothing that you can do about him driving with a suspension other then to wait it out for him to get locked up for it...
If you want to prevent him from driving eith your son in the car while he has no license then go to your states family court and get your custody agreement ammended to inculde your concerns of driving your son around with a suspended license. If a judge specifically forbids it and he is caught, it's off to the local precinct, with a few extra charges tacked on.