it was his little brother, what did you expect? he was just being supportive
it sounds like even in the point where you killed the overhead that the little brother had set up the point well so.
yelling fuck off wasn't cool
you were probably just angry that you were getting destroyed by a younger, less experienced player
also, as already mentioned, the fact that you label your practice partner as a 'pusher' makes me think you don't respect his game nor possibly his little brothers (because they're probably better than you?)
facebook is not a big deal and he was right, if you can't handle some cheering (even if somewhat obnoxious) from the sideline and lash out then that's not cool
maybe you should start playing ping pong or something you won't get as upset about