Jellyfish Sting!
Caroline will ask her brother in law later, between him and her sister, maybe he will be the one with the kind soul and would willingly give her permission to stay in his condo unit. If John will allow her to stay with them then her mean sister has no other choice but to accept her boyfriend's decision. After all, John is the master of the house, he was the one bringing in the money into the table and not her sister.
Even if there is a big possibility that John wont allow her to stay with them, she can at least try to ask him. But if he refused then she will accept his decision wholeheartedly without hard feelings.
Caroline was done sulking, she swam back to her sister's side. She must not display displeasure or antagonize her pregnant sister, right now she was her only gateway to the world of wealthy men.