I’m so sorry for your sister and hope she will get out but you’re projecting those concerns onto Carrie. Just a reminder that these threads are about her and no one else. She goes on tours without him and travels without him, that’s nothing like not being to even leave the house without him.
Carrie controls everything about this relationship, including Joel, it’s not the other way around. I’m sure Carrie would have a laugh reading certain scenarios like him being abusive and controlling, maybe she’s even taking notes. This will serve her well when she will eventually dump him and want to rewrite the entire narrative.