When playing a Lawful character. I declared my character to have exited a room already when stuff happened that would have made my character otherwise want to report the party.
According to Pathfinder lore for changelings, it is unlikely that your dad would have also been a changeling (but I guess it could work).
Also, it would be just a difficult to tell as any other being that gained a transformation spell/ability. Being a changeling doesn’t necessarily give any kind of transformation ability.
When playing a Lawful character. I declared my character to have exited a room already when stuff happened that would have made my character otherwise want to report the party.