This is key. His path of past success can hide his internal naivety and mental weakness.Sudden suicide can always be traced back to some history of hidden depression or internal struggle, especially for those "seeming successful" students in school work.

If his friends were able to check up on him very often and to talk with him more on this episode, it could have been prevented.Talking is a very powerful therapy for this kind of illness (or situation).

Too late......too sad.