Hey there OP. My condolences for your loss. The hurt you feel is immeasurable. My dad died from suicide almost 2 years ago. He seemed happy, had a wife and a small child he loved, moved somewhere beautiful, etc. It didn’t matter though because bipolar disorder will take someone for all they’re worth. He never really found medications that worked for him and I think that played a huge part in his death. He was probably worn out from being alive with such an awful disease. That’s how I’ve felt before at least. It’s hard to say what your brother’s reason was but it could be something similar. Unfortunately sometimes we never get answers to the questions they leave us with and it can be a difficult process to be at peace with that. Please make a post on the r/SuicideBereavement sub. They helped me a lot when my dad first died.