Like most of you, I had a small arsenal while growing up, I had a German Luger, a couple of .22s, and a couple of shotguns, but the truth of the matter is, I didn't OWN a single gun, they all belonged to my father, but he let me use them, and call them mine.
I suspect that may be the case here, can a 14 year old legally own, or buy, a firearm? In most states the answer is no. His mother bought the guns, so legally they are hers. Can she be convicted for allowing him to say they were his? Maybe she can be held responsible for allowing access to the guns without supervision, but I really don't think the case will hold water, especially if she can afford a lawyer. JMHO.