This was something that I simply couldn't stand the thought of and if that happened, I wouldn't agree with this.
Welcome.
Dont EVER accept this doctrine from her. She is speaking about long held teachings from her childhood but they are deeply flawed. Children & parents HAVE died because of this. Sacrificed for a man made organisation.
You`re feelings as above will terrorise you if you have to watch your kids live the JW life.
PS - Gently ask her if she would feel ok about having nothing to do with her 18 year old son if he was disfellowshipped for having unmarried sex. Yes, having nothing to do with him, EVER again, as long as he lived (unless he came back to repent as a JW). Crazy I know, but this is the doctrine. Personally, I would rather tear my heart out. You will only understand when you have your own kids, how utterly unloving and cruel this 'bible doctrine' is.
PPS - When challenging her on anything, just say you heard about such & such a thing in the paper or from a workmate. NEVER SAY YOU READ IT ON INTERNET - BARRIERS WILL IMMEDIATELY GO UP.
Jambon