just think about it.........have they left even the SLIGHTEST hint that he is konohomaru's dad? for one thing, they wouldve acknowledged in some way about him being the son of the 3rd during the 3rd's funeral, and another is that im sure he wouldve been the one comforting konohomaru instead of iruka during the funeral as well. Maybe its just a common last name, or maybe he's just a nephew of the 3rd......