Statistically, most folks do not leave a note when they commit sucide. And thus, the family never knows why.

All of the other comments on this subject pale in comparison to the grief, sadness and overwhelming disbelief that his family is going through at this time. Losing a loved one to sucide is tumultuous! And for the rest of their lives they will learn to live with it, but, never forget it and will always ask, "Why?" and "What could I have done?"
I have worked in the field of Suicide Prevention and Postvention for 12+ years and have experienced the loss of my sister by suicide. NOTHING prepares a family and friends for the grief they will experience. It is different from all other grief. My heart and my prayers are with his family!!!