Hi SnailsPace2!
The best thing any parent can give to their children is a childhood. A good honest normal childhood. But only you as a parent can give this, not grandparents or any other family member.
Very early on when me and my wife left, the first thing that the G parents asked was "can we take them to the meetings sometimes?" Our answer was a heavily stressed NO. No meetings, no talking about meetings, no 'such and such says hello'.
We even went so far as to say that contact with our children depends on you doing this for us. We got past the shunning thing straight away by putting our own parental conditions on everything. You must get in there first.
I am happy to say, the G parents are now into their own fade with my Mum in law missing all meetings since this June.
You never know, they may start asking you questions about this controlling cult. All the best!
GA