Salowman's Manga

i think that the middle brother and him will end up together. The story just gives off the feel that they will end up together. Plus the relationship chapter for the middle brother was longer and it seemed that the author put more effort and thought into that chapter. Also, the author put in that part about the middle brother saving him when he was drunk. Although its hard because if it were the older brother or younger brother (if he were older) they probably would have done the same. i can only assume though.