We can only assume I guess. People,patients who are constantly in pain chose death than being alive. Some families would chose that as well to end their suffering..althu his mom was in cahoots with the girl. this i can understand, althu there are times when i hate seeing someone suffer, accepting when death comes knocking.
Now this guy, who had live life to the full, in pain every second. Perhaps he longed for death every second that he's awake too. What is there to live for? I may not understand the way he felt for not experiencing his situation, but having asked the same question, I understood then why people have jumped over bridges and buildings..when all hope is gone, there's no more reason to live. That man wakes up each day for the same pain and torture as yesterday. If I were him, i will hope to not wake up in the morning.

For those who are suicidal, we can try to watch and control our thoughts for our actions follow it. Holding on to God and having the strength to follow His will keep us sane and endure the pain and overcome.