Perhaps it could have been tortured out of him, had they been related.
However, I have intended to role-play that character as wholly unrelated to anyone else, once he got good enough at being an advy to warrant approaching nobles for trades. Since I can't make another account, but I still want to experience the commoner game-play, I have no choice but for him to show up as a member of my family. I also couldn't choose the realm he was spawned in, and I happened to roll Terran.
I've received your apology in the game, and I accept it. However, I think this is still something that needs to be discussed, as anyone who, like me, spawns a character by random in the territory of an enemy of their nobles characters could face this same situation. Is this something that needs to be prevented? Can we place a warning somewhere, or allow people to hide their advies?