Responses
If at least she was like: "I seem indifferent because I know she likes to be alone or because I understand that we have different tastes, but it can still be seen that she appreciates Serena or that she seeks a healthier coexistence between her daughters", but she doesn't consent as much. one that does not allow her to mature and turns her into a spoiled child and neglects the other so much to the point that a reconciliation between the two is impossible.
The mom really be giving that "There was always something wrong with this child"-monologue that you see in serial killer interviews with their family.
She's allowed to feel this disconnect, but bfr and try to do something at least. She for sure must've known how isolated Serena was, yet she did nothing but make dumbass comments. She spams Rosemary with the motherly affection she wasn't able to give Serena in a bit to reassure herself of being a good mother. Meanwhile Rosemary is never properly disciplined and forced to face reality, so she doesn't have the chance to mature and face herself.