I am new to the site I and I hope I am doing this in the right spot. However, I think I know who Dumbledore's Brother is. I think he is the bartender in the Hog's Head. Here is my evidence. In HP4, Dumbledore mentions that his brother got into trouble for doing experiements with sheep or goats (I can't remember which one right now). Well in HP5, when the kids walk into the bar, they said it smelled of sheeps/goats. Also, it goes on to describe the bartender as being strangely familiar. The last piece of evidence I have is the prophecy. REmember that when Dumbledore was meeting Trewlany (sorry if I spelled that incorrectly), he did it at the Hog's HEad. Somone was spying and the spy was thrown out half way through the prophecy. Who threw them out? Possibly the bartender. And why would Dumbledore go to the Hog's Head, which is dirty and ugly, to interview a new teacher, rather than the Leaky Cauldron or even stay at Hogwarts? So there it is. It sounds like a JK clue if you ask me. What do you think?