is there a way to find out what email was used as the alternate email for apple id set up?

So I just fixed a family members old iPhone and they don't remember the information like password or answers to security questions but they only remember the Apple ID. I tried calling Apple support and they asked for CC info attached to account but they don't remember ever putting any CC info when they set up the account but it does have a alternate email but don't know the exact email since Apple only gives u the first letter of the enter email address. If I can figure out how to see the remaining letters or even like if it's from aol or gmail or whatever maybe I can help the family member figure out the password recovery better.