ETA: Let's be real here mom, you said you didn't qant to be the "bad guy" that takes things away, but you recognized just how dangerous this was, you knew you didn't want him to have this, you knew he wasn't ready.

But you let him keep it because of some petty reasoning that boils down to a competetion between you and your seperated husband.

That being said, everyone else is just as wrong: your son was stupid and fucked up spectacularly, your husband gave him the tools to do so, and doing it without telling you because you probably wouldn't have allowed that.

But don't play dumb, you're a good mom, you know that all you had to do was take the gun away from your kid and noone woulda gotten hurt, but you were trying to be a "cool mom," so how about it? Feel like the cool mom or the bad guy now?