I think you are missing the real story here. When the Gub'ment revokes your license to sell guns it means they have deemed you broke the law. This owner is in danger of being incarcerated. He's probably not worrying much about advertising.
Obviously we don’t know all the facts and he may have done something illegal, but, based on the reactionary ways of this administration, I am assuming the owner is not guilty of anything other than be the unfortunate person that sold weapons to the mother.
It reminds me of Hillary promising a family member of one of the Bengazi victims that they will hunt down and punish the maker of the inciting video.
Another thing that comes to my mind: I guess these days they can find a law that anyone has broken if they want to, Gibson Guitars comes to mind. Must be using ‘Atlas Shrugged’ as a playbook.