From what I've gathered from several news articles, he was already under care of therapists for some other conditions (some specify Asperger's Syndrome, but many seem to omit this for some reason). His parents then became aware of the fact that he's been posting videos that most people would find at least alarming, e.g.:
So they notified both his therapists and the authorities, but after a chat with him they figured out everything is A-OK.
I mean, fine, he doesn't sound like he's about to go on a killing spree, but it sure as hell looks like he needed an intervention. It's probably not as clear-cut as "lol they didn't give him enough attention", but it really does seem like it could be prevented.