I've known a number of witness families who went this route. Frequently, the "teaching" responsibility fell on the mother of the household. Can you imagine adding to all the things a witness wife must do the additional heavy burden of "schooling" her children? It's a recipe for a nervous breakdown.
I recall one home-schooled 12 year old boy in Arkansas. He was already a Regular Pioneer, took the lead or prayed at midweek meetings for service. By all appearances he was an extra-short middle-aged man with a high voice. He had all the JW lingo down pat and impressed all in his congregation with his "maturity." One elder in his congregation told me that if he were a little older, they would recommend him for ministerial servant in a heartbeat.
I do not know what happened to this young man, but I do know that he was brought up totally insulated from the outside world. He would be about 26 now, so he maybe on the verge of eldership or self-destruction.
tms