There has to be something actually wrong with him that he did something like that. I'm sure every kid had a moment in time where for a split secondt hey thought life would be better without one of, or both of their parents (which, in the first place, is obviously untrue). But to go this far? That's... Sickening.
Maybe the game got him thinnking death wasn't even real, but... Correct me if I'm wrong (never played it) but in Halo aren't you shooting down evil monsters, or bad guys? And he really thought that his mother was such an... evil monster, or whatever?
Meh, this whole thing makes me insecure. That if I have a child, and try to raise him the "right" way (you know, appropriate punishments, taking things away when they're bad) that I may as well be killed. That actually does worry me, I've thought about it alot. But for every parent, and every child, there's always that chance...
It's also scary somebody who you put years of effort into raising, giving a home, giving food... giving an expensive Xbox... to, would snap that easily. I agree with whoever said that he should be put in a psych ward / insane asylum / whatever you want to call it. Jail will only screw him up more..