If he had depression there might not have been a reason. It’s not uncommon for men to spend their lives silently fighting with depression, and when I was 5 a man going to a therapist would have been seen as a weakness and weird.

Remember that depression is a disease, looking for a reason makes as much sense as asking why someone had their heart fail. I recently watched “In Limbo” with my wife and I think they handled it very well (TW: Suicide). When the depression grabs you you’re not able to think clearly or reason your way out of it.