I don’t know about useless - a locked door is useless if your philosophy is that someone can kick down the door.
However she needed to meet her responsibility to make sure her firearms didn’t fall into the hands of a psycho - my point is that she FAILED in that responsibility.
These discussions are endless and almost useless. For example, she did keep guns locked up except 1 by her bed for protection. A discussion between them escalates into argument or a threat to mom’s life. She goes to bedroom to get the weapon to defend herself and son gets to her before she can defend. He takes said weapon from her and kills her. That is hypothetical but as likely a scenario as any other. It is a tragedy without clear answers at the moment at least.