Tbh i kind of think lestat was right (you hate to say it) when he was like you can’t just choose a new family configuration. Not because he’s Claudia’s maker but because they raised her… she was a child and they brought her up. They are her parents. But its very interesting that “we’re brother and sister” is like, a little folie a deux that Louis and Claudia need to keep their relationship afloat
I feel like the most obvious thing it does is absolve Louis of responsibility for not protecting Claudia from Lestat’s abuse and for his own failings as a parent. She can forgive a sibling who never had any power in the family dynamic from the start in a way she can’t forgive a father who chose this relationship and chose to bring her into a dangerous situation and then made choices over and over that kept her trapped there