Mental health is a lot more complicated than that. A visible external cause isn’t necessary. Things are completely normal people wouldn’t have any problem with can be extremely traumatizing to someone else

Teenagers may not have the life experience to handle what adults find simple.

Neural divergence can be a major factor as well.

Telling a child with ADHD they just need to try harder is a recipe for life-long self-hatred.

This is exactly my point. I said "life failed him" not "he failed life". All of your examples are the environment around you not giving you sufficient support. Struggling because you have had traumatising experiencing or neurodivergence should not be normalised. Labelleing someone as neurodivergent shouldn't be an excuse for us to be ok with them suffering. Getting to the point of considering suicide should be seriously examined. Society needs to do better to support people of all varieties.