@Confused I think it just an implication of showing how actually in real life we ship PPL even if it does not become real, like if they are really really close, and yes in real life nobody in their right mind would write a fanfic using the real name specially a family member but PPL do take inspo and I think it's all a metaphor for just this, if this was real I imagine she would have made up imaginary names for the characters but I believe the author wrote it this was just to give us a clear vision of whom the sister is specifically taking inspo from making it more relatable for us...