How to remove an email from account

I just reset my apple id password, and my dad received an email about it, which isn't necessary. In my account I can't seem to figure out where his email is connected, so I can't remove it. It also has nothing to do with "family sharing" as I have never used that and after checking I saw that no one was connected to that anyway. Does anyone know where or what his email could be connected to and how I change/remove it from my account?