Fading with children is difficult and very hard. Staying in a religion that restricts their childhood and isolates them from their peers is extremely damaging. We wanted thenm to have the chance to make real friends not conditional ones.
When we faded our children were 7 and 9. Our son has aspergers so it is also impossible for him to keep a secret. We had to make choices about whether to live as JWs but no longer go to meetings and on service or whether to allow them to have a normal childhood with the risks that would entail. We went for the later. I had seen how the belief system was harming their ability to relate to others and causing them to be isolated. This meant that the fade could only be maintained for a limited time. Part of this was because as parents we realised it was unfair to make the children responsible for keeping a secret from family. This is a big thing because later on if they blurt out something to their grandparents that leads to a JC and Df'ing then there is a possibility that they may feel they are to blame for the bad things happening.
We were honest with the children from the beginning but made it clear that whatever happened it was our decision not theirs and as their parents we were responsible.
I wish you luck we have not managed to maintain all family relationships but 3 years on I feel we did the right thing for our children.