Answer:
As far as I am aware, this is false.
Explanation:
From what I've read about egyptian mythology, Anubis does not have a brother, only a half brother, Horus. What you've heard could be coming from a work such as Rick Riordan's The Kane Chronicles, where Egyptian mythology is adapted into novels, sometimes with various changes or additions (although Rick Riordan does do a pretty good job at keeping things authentic).
