I get it, but would your family described you as mentally ill? Then do nothing while you sat outside handing what they themselves described as a, “Machine gun”? If someone I knew was mentally ill and I saw them playing with a ‘machine gun’ I’d run and jump out the window.
The closest weapon to AR-15 I have ever owned is a M-1 Carbine. I don’t own an automatic weapon ‘cuz I can’t afford the cost, the tag, or the ammo! Also, I like old guns.
As for mentally ill, I am pretty sure all of ‘em think I’m not exctly right in the head... :)
As I said, I think they creating a legend for him - providing material for his defense. If I thought someone was dangerously mentally ill in my house, the guns would go to a storage unit or a neighbor, and the individual would go to a doctor.