Sorry to hear that, many people commit suicide for the wrong reasons.
I say this in the hopes you will not grieve; only understand that he may truly be "happier", for lack of a better word, and in an odd way perhaps rejoice that their pain has been lifted.
For some though it is bittersweet, like in the case of my aunt and godmother. While we were all sad about the fact, she finally was out of her misery, after years of struggling and being constantly on painkillers to cope with chronic pain. Numerous surgeries failing to help, and a constant haze of painkillers she was on, combined with the isolation of where she lived and her job she had no choice but to keep. We all tried to help, but none of us were able to to.