This question is very similar to this one. However, I felt it was different enough, and I also did not find an answer.
In the tale I am currently writing, a girl, whose parents have both been long dead, is talking with her adoptive father. I'm having trouble referring to him.
Normally a name is what would be used. However, I don't want to use a name because the girl thinks of the father as her actual father (She knows he isn't her true father, but loves him as if he were). It's the same relationship. Therefore, referring to him by name would just be weird.
Simply using 'father' would be the next option, except I don't want to do that. The reader does not yet know that the father is not the girl's actual father. Therefore, I don't want to refer to him as the girl's father, because when I reveal the truth, that could get confusing (This question is actually the main bridging conflict, so I can't really remove it).
The father has a daughter of his own (referred to here as 'Y'), so I've been referring to him as Y's father. This has worked, but I have nothing else to call him, and the repetition is showing. Removing taglines (the scene is mostly dialogue) and utilizing pronouns has helped some, but I can't use them everywhere.
How can I refer to this character, who is too familiar to be referred to by name?