I knew a family in this situation very well. The husband was Catholic and insisted in raising their children in his religion. He didn't allow them to go to the Kingdom Hall ever. The JW mother "studied" with the kids every day after school while the father worked. The elders sanctioned this, and she was such a self-righteous, "long-suffering" role model for the congregation. By the time the kids were in their teens they were indoctrinated witnesses and both got baptized.
The mother got a "scriptural" separation on the grounds of "absolute spiritual endangerment", because he lost it and went over the deep end. The couple eventually divorced. Both kids married JWs and are still in and have nothing to do with the non-JW father.