Re: Confused
How about just leaving her alone and minding your own business instead of worrying about what she is wearing, doing, etc.? If you get lucky, maybe she and your brother-in-law will move back to the west and then you won't have to worry about what she's doing all of the time.
By the way, I wouldn't use a phone conversation to judge her knowledge of Islam, and it is always possible that she is more knowledgable than you, and that you are confusing culture with Islam. Many converts tend to be very knowledgable, and don't take the decision to convert lightly.