00Dad, My heart goes out to you. Having a beloved child shun you is so painful and cruel. I don't know the circumstances of your divorce with their mother but the thought occured to me that your boys might be feeling protective toward her. They may be embracing her religion to try to show love and support if they think you "wronged" her. Just having their father leave the house is enough to make some kids angry enough to want to strike back so to speak.
My son was 17 when his father and I divorced. He wanted to take on the role of "man of the house" often encouraged by others at the KH. He was angry at his father for what he saw as abandonment. He was a true source of comfort for me at this difficult time and I must admit I drew comfort from my sons "loyality" toward me.
Your ex is undoubtedly delighted at your sons loyality toward her and the WTS. Besides thinking that they will gain Gods approval, therefore eternal life, it is a form of "winning". Winning the divorce war. No matter how much she may dispise you now, she lost much. She lost her family, her provider, her partner, her confidant etc. etc. When her sons pick her company over yours, her religion over yours, she gets the validation she desperately wants and needs. However, things can change. They did in my case. What drove my son right back into the waiting arms of his father? (who was also DFed) Was it a change of heart about the WTS? Religion? Absolutely not!
It was the fact that I found ANOTHER man to love who loved me and married me. Another rooster in the barnyard! Now, in his eyes, I didn't NEED his loyality and protection anymore. Even though he HATED the idea of me being with a new man, he felt free to see his fathers side of things. He and his sister moved in with their father the minute we returned from our honeymoon!
The best possible thing for your relationship with your sons to resume would be for your ex to move on and remarry. To need them less in their eyes. Do you know anyone who you could fix her up with???