Well, I don't know what the league considers going into the court, but it is just any body part inside the playing area, and if the father of this kid is the one on his right (from the camera POV), his arm is clearly inside the court as the clock is winding down, as his foot is about 6 inches from the sideline and he is pointing at someone during the play.
In any case, I don't think that can really be considered a serious push. A 6'8, 300 lb man "pushes" a 12 year old and the 12 year old is still standing?