Just came out to him and he is really supportive. We talked for almost three hours! He said he's not surprised and that he just wants me to be careful. Yea, I don't know, it was easy, and now I feel really light, I guess. I kind of beat around the bush and tried to make him guess but then I just plain out told him and then he asked a lot of questions and said that I should add an H to my name, which I kinda like. It was really awkward at first but then it was easy.
And yes he leans a bit more towards men, actually we've got about the same taste, we talked about that too. And yes, I know some homosexuals are against trans, but he just said that he's open minded and that it all makes sense now. And he then joked that since he already calls me "midget" that for kicks later when I can pass better that he'll call me his sister just to mess with me cuz that's what littleBig brothers do. i.e., he's younger but 6'4" (I'm 4'11"), hence I've always called him my little/Big brother.
So, it all went well. It seems like siblings are more understanding and welcoming than parents.