When my friend emailed me a "goodbye", I, another friend, and the police arrived in time to save her. She is bipolar, and she hadn't been taking her medicine. She said that her life belonged to her, she had a right to do with it as she pleased, and what she wanted to do with it was not live with any more of the pain.
Saving her was a matter of convincing her that God gave her life in the first place, so she wasn't given permission to take that life.
It would be terrible to face, but I don't think your brother had the right to take his life. That leaves the question I have of God, if my friend had been successful it was the physical lack of a chemical in her brain that was the reason she wanted to kill herself. Would God forgive her based on the reason she had that desire?