I've said it before on here and I really wish people would do it. It's time people reverse shunned these absolutely vile, toxic people.
Theres no way I would allow my children into a situation where my mother doesn't speak to me yet has contact with the kids. No way. What would this teach your children about relationships? What lesson would it teach your mother about how she treats you?
Reverse shunning drives Witnesses crazy. They hate it. It disempowers their ridiculous power/guilt trip.
Give them nothing. They're frankly not worthy of you.
"No natural affection" - fulfilled by Jehovah's Witnesses.