Our son finally has relented and allowed his young daughter to spend a day now and then with my wife. He has confided in me about it being "bad association" for his daughter because of the witnessing he knows my wife will do. Sure enough, out come the Caleb and Sophia videos and the poor grandchild saying to her grandmother, "I want to make Jehovah happy, too."
The parents of our other set of grandchildren made it clear, no Bible Story Book, no indoctrinating their children. And my wife pretty much honored that. My son is not very likely to be so diplomatic. And he has a right to put his foot down. Those videos are toxic!