Sounds like facing his mother is what made him do it.
Sounds to me like he was already suicidal. And his mother knew it. This confrontation by authorities may have been a final straw, but I'd bet this boy was mentaly messed up and contemplating suicide for some time.
I can’t even imagine how painful it is to be a teenager actually having sex with every new boy/girl friend like they do.
Just having sweet pure dates at that age was beyond passionate and stressful. I don’t know how I survived then - these new rules of amorality are deadly.