[quote=IVIasterJay]I'd kind of created him with the idea that he'd have never had contact with another Hozuki except his mother and old memories of his father.
[/quote]

Just because they're of the same clan doesn't mean they know each other. Kirugetsu left Kirigakure before Agini was even born, was in Amegakure when the Sai Conflict began, moved around with the Rebellion during the war, and only just settled down recently. He and Agini could literally have no knowledge of each other.

So there's nothing really to be bothered about.