For everyone who says "we didn't recognize the cries for help", try this on for size:
From the looks of it, the kid stalled in track, was dumped by his girlfriend, didn't get into college, and who knows what all at the same time. That's a lot from the perspective of anyone, and certainly an 18 year-old.
We all should pay closer attention to the plights of those around us. At MIT (now) they have an initiative called "TMAYD" = Tell me about your day.
It can make a world of difference.