The loss hurts, to be sure. Children don't understand why they have grandparents who don't want to have a close relationship with them or their parents.
On the other hand, be grateful that these children will not be indoctrinated behind their parents' backs by JW grandparents who are undermining parental authority, and eventually hope to turn the grandchildren into loyal JWs who will shun their Disloyal™ DF'd or DA'd parents.
Mr Scully and I decided together that any time our children spent with JW relatives would have to take place under our supervision to ensure nothing of this sort took place. Eventually, as the children became more independent, they wanted little to do with JW relatives. We taught them what JWs believe, and they came to their own conclusion that the belief system was not for them; nor did they want anyone preaching at them or praying for them or disrespecting their father by shunning him. (He was DA'd by answering a trick question when a couple of Elders™ made a Shepherding Call™ many years ago.)