My brother is astoundingly intelligent, and it makes me depressed about life?

I'm not exaggerating when I say that my brother is probably some kind of genius. He was just born with this incredible intellect and capacity to understand everything on a profound level. Lately he's been considering suicide, and my dad was just having this conversation with him about it. I didn't understand most of what my brother was saying, but he was destroying my father's "arguments", I knew. His understanding of human nature and psychology is just amazing, and he treats complex subjects like they are common knowledge. Seeing how he picked apart my father, who most people consider very intelligent, in a way it degrades me and makes me feel like I'm just a drag on humanity. I feel like if there were more people like him and less stupid people like me, he wouldn't want to kill himself. No one is able to help him because no one truly understands him. So it seems that I have 2 problems here: 1) What can I do for my brother, and 2) How can I feel better about my own existence? He would probably scoff at the idea of asking Yahoo!Answers, and the fact that I feel the way I do (were I not his sister).