How ironic! when my jw first joined up my kids felt they had become fatherless! I also felt like I had become practically a single mother. I knew divorced men with only partial custody that spent more time with their children. Back then they still had the 2 meetings during the week, he was gone every week night but 2. Tues was a meeting night, Wed his bs study, Thurs another meeting, Sat morning fs, Sunday 4 mind numbing hours again. That left Friday night which they also tried to take until I put a quick stop to that one and Monday night was free. By then we were so disgusted by him we didn't care if he was around or not.
Things have since improved but the kids still hold some resentment. Can't imagine what how things will go if grandchildren come. My guess will be that they will never leave kids alone with grandpa or maybe be honest and tell them grandpa is in a cult don't listen to his religious nonsense. Time will tell.