So, I'm waiting to see what they find in his apartment, but there's very good chance this guy has severe mental issues.

Instead of saying "Don't blame the guns, blame the people!" I want to say "Don't blame the guns, lets get people some help". I think the best way to do that is to donate to some mental health charity or research. The mental health care in this country is piss poor, and people that need help don't or can't get it. A lot of it is difficult to change (people can't get involuntary help unless threatening harm to themselves or others, and even then it's very difficult) but I'd at least like to try and make a difference.