You're not going to get through to the mother, not if she's been this way her whole life. She has made a lifestyle choice -- that this is what a woman is supposed to be -- and to change would undermine the core of her existence because she doesn't see change as an option.

The daughter is a younger version of her mother. She got her values from her mother (and perhaps the larger Mormon society.) I'd also bet that the sister is lying for the girl because the mother told her to say that.

Yes, they are all brainwashed in a sense. No, you probably can't change any of them. They are taught a certain way, and they believe a certain way because they have chosen to be like that.

Ultimately, it's a lifestyle choice. And unfortunately, you'll probably have to fire the girl.

I know this wasn't the answer you wanted to hear.