You can feel what you want, but if I had a child like that, I would be 110% sure he couldn't get at firearms. Mainly to protect himself. That's just my opinion. I also don't believe anyone NEEDS an AR-15/M16 type rifle. Again, my opinion. My father had a few guns while we were growing up. Never let me near them, never even see them. I learned early on, they were his, I was not to touch them. He was clear on why he had them (personal protection), and they stayed where they were for years, until he eventually sold them all when we needed the money.
http://www.huffingtonpost.com/2012/1...n_2311009.html
By the way, this is a fairly moving/eye opening essay by a mother with a child that has a severe mental illness, how difficult sometimes help is to get, and also the dangers. So yes, it's quite possible she simply lost control of him, which I don't blame her for at all. You're right, he could have built a bomb, he was very smart. I couldn't have blamed her for that. But to make it that easy for him to get guns and all that ammo, that's just plain careless. Would it have prevented the massacre? Maybe not.
Look, I don't have the answer. Sometimes mental illness is just not well enough understood to help all people. Sometimes the help is not there, due to shitty healthcare. Sometimes it is, but the parents are somewhat in denial and unwilling. But either we must do something, whether that involves greater security, less guns, and/or more mental health awareness and responsibility, I don't know the right mix. But something substantive needs to be done. It may well mean the NRA has to give some up, that the privacy advocates have to give something up, etc. But either that has to happen, or we just need to stop giving a crap at all and not even report these massacres. At the least, why can there not be rules that prohibit mentally ill people from getting near legal guns?