You don't actually have to do anything. Just be honest with her and the rest of the family about your political beliefs and call out her cultish behavior. She'll either moderate her ideology enough to be tolerable (at least around you) or she'll throw YOU over, showing how much she really cares about blood. Either way problem solved.

You don't actually have to do anything. Just be honest with her and the rest of the family about your political beliefs and call out her cultish behavior. She'll either moderate her ideology enough to be tolerable (at least around you) or she'll throw YOU over, showing up much she cares about blood. Either way problem solved.