SaneAgain,
Welcome. Different approaches work for different parents. My two children were considerably older than yours when I left Wally World but this is what worked for me. I did not try to persuade them as I knew their mother and other JWs would paint me as Satan trying to mislead them. I also knew that no decision is more meaningful than one that comes from ones own conclusions. So I was patient. As I was leaving the organization and after I was completely out I always answered any questions they might have but tried not to talk them into anything. It took some time but as they saw my life blossom and improve considerably, education, career, travel, relationships, overall disposition, etc., they began to see the light. There were some tough times and struggles but I am happy to say they are both out and thriving. The decision they made to come out is their own and it is solid. I could not have a more wonderful relationship with both of them. We are all happy to be out!