This is absolutely horrific. This guy is allegedly responsible enough to have a gunsafe (or other type of locking mechanism) and take his kid to gun safety courses - and then loses the key under the couch? If the guns were for home-defense, this idiot would've been in for one hell of a surprise once he got out his keychain and looked, and looked (and looked).
Then, he finds the key, and hangs it on a wall hook? A wall hook? What, didn't he recognize the damned thing? That's like locking the front door and leaving the key hanging from the porch windchime. I'm not going to say this guy deserved what happened - nobody deserves to see their own kids die - but Jesus, what a price for negligence!
I'm all for gun rights, but too many gun-rights advocates like to rush like fricking Superman to the defense of an attacked Gun Owner, forgiving or perhaps just overlooking grave mistakes such as the ones this guy made. So he had the guns in a place where they would (in theory) be secure. What, does that mean we give him an "A" for ◊◊◊◊◊◊◊ effort? And it's true that if the kid really wanted to kill himself, he didn't need a gun - he could have used a kitchen knife, or OD'd on aspirin, or hanged himself in the closet with his belt. But this kid didn't just "really want to kill himself", did he? He took two pistols, three rifles, and 2 shotguns - along with who-knows-how-many-rounds for each of them - to school. I suppose one can make the ludicrious argument that if a kid really, really, really wanted to kill his classmates, he could've used kitchen knives...
Look, this poor guy's learned a lesson that nobody really deserves to be taught, and I really don't think he needs to go to court over this. First impression I get from the article is that he really is a nice guy, and really didn't want anyone - much less his own kid - to be hurt. At worst, I believe this guy was simply a victim of ill-timed absent-mindedness. But damn it, that doesn't cut it when it comes to guns. It is entirely unacceptable! I don't care how nice of a guy he is.