Hi J-DUBBED, Don't send your son any videos, books, or information about dangerous cults until he asks for your help!! I know that it sucks that there is no magic pill to awaken your son, but that is the reality of the situation. Talk with a professional, like Steven Hassan, if you want to improve your chances and reduce your frustrations. It will cost you though.
If you cannot afford professional help, just learn and practice as much as you can about empowering his authentic persona to critically think for himself and what to say to reach his authentic persona and how to turn-off his cult persona. Focus on controlling your emotions and actions to improve your relationship with your son. Your goal is to help your son critically think for himself. The more opportunities that you have to ask him simple questions about how does he feel and listen to his answers: the better.
I hope that you post more threads asking about what to do, and talk with someone about your frustrations so that you do not explode at your son or his wife.
Best of wishes.
Peace be with you and everyone, who you love,
Robert
P.S. - If you want to become politically active and possibly help your son, please read the thread http://www.jehovahs-witness.com/topic/49120004/revise-tax-code-protect-children-from-sexual-abuse?size=10&page=1