How would you deal with a friend in a family cult?

I got out of a familial cult. Everyone needed to have the same opinion, and they all needed to validate it by asking each other questions. To get approval, you have to call a family member. They expected you to agree with them when they talked about each other. You will be discussed if you distanced yourself from them. Family members turned to my sister for guidance and other matters, and she was always correct. They paid attention to her and her only. Everyone needs to rely on one another for topics, guidance, knowledge, and much more. You had to follow everyone else's lead as well. You must remain with the family, and if you attempted to improve yourself, they would drag you back. My birth mother was terribly abusive and a bully. This was accepted and you weren’t allowed to stand up for yourself. All bad behavior was accepted and followed but my sister was the queen of the family.

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I forgot to mention that you had to surrender your rights basically or they go against you
How would you deal with a friend in a family cult?
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