"I didn't press her to break her promise, but I did ask her, "could you find any flaws in his logic?"
She paused a moment, but conceded that no, she could not."
I believe that there are more people than we can imagine that feel the way your friend does. They can see it. I have a friend that I confided in and he agreed with everything I said but ended the conversation that..."if you do not return, you are going to die." That fear gets em every time. The social part of the cult is just something others can not give up. They just can NOT "cross over", no matter how logical you are. Crazy!
I actually quit trying. I found myself getting so frustrated. My spouse and I concluded that they will have to figure it out like we did. It is just not worth the frustration. Now we use that time to enjoy life. It's short!