When my best friend of 30 yrs. first told me she was involved with the JWs, she had been "studying" off and on for over 9 years. Since we are very open and honest with each other, I found it interesting that she had never said anything about it for so long, and when she did finally tell me, it was like she was worried about what my reaction might be. At the time, I thought the were just another denomination of Christianity. I didn't comment one way or another.
Then I met her guru, and she started a very long and uppety schpeel about heaven and "paradise earth", blah, blah, blah,..... and something just did not seem right. That was when I started doing some investigating. When I found out it was a cult, I thought, "I better warn my buddy!" But before I had the opportunity, her brother-in-law beat me to it. His method was not appreciated. After hearing about that interaction, I knew I better keep my lips zipped until I figured out how to do it a bit more effectively. I needed to do a lot of research and find out how others became free.
David Reed wrote a book called Rescuing Your Loved Ones From The WT. He gives a good description of an arsonist that wants to burn a building down, but he wants people INSIDE the building to burn as well. In order to pull this off, he dresses nice in a suit, goes door to door in the building, and politely tells them that there is a sniper in the area who has been pounding on doors and yelling "Fire!", then when the people run out in a panic, the sniper shoots and kills them. After he makes all of the people afraid to leave their apartments, he goes outside and starts the process of setting the place on fire.
While he is doing this, another guy who knows his diabolical plan, has to figure out how to get the people out of the building. He knows that he has to do something, but what? He starts to calmly go door-to-door and asks if the people would come out in the hall so he could ask them a few questions. When they step out in the hall, he asks, "Wow! Do you smell something? Doesn't that kind of smell like smoke? What do you think that glowing area over there is?" Until THEY come to the conclusion on their own that there is indeed a fire and they better get out of the building.
You have to by-pass the implanted fear, by making subtle points. And it takes a whole lot of patience and time. I studied for several months on how to reach my friend in a non-combative way, and am starting to see some progress after a couple of years. The upside of doing this NOW, is I believe it has caused her to hold off from being baptised. In your situation, I think if you ask the right questions, and do it with the right attitude, not only could you cause your son to delay his baptism, but you could also plant some seeds in your daughter-in-law's mind. But you have to realize that it is a slow process and that you have to be careful, non-critical, and VERY patient. You also have to do some research.
Keep all of your resources out of their sight. Do not hand them a book and think they will read about the down falls of the WTS. Don't say anything negative about the WTS. Find some good questions to ask, and don't press too much when they are cornered. Let them save face and drop it for awhile. Small doses. There are tons of suggestions and many people (on line) willing to help along the way. If I can be of any help, let me know!
The most difficult thing for me, has been trying to find people in my immediate area who know how to help. If I wait for my friend to knock on the door of someone who knows how to ask the right questions, it's not likely to ever happen. I wanted to find the "quick fix". I have found that there isn't one. I have also found through my searching, that I have had to become a reluctant expert on the subject, and in turn, have been able to educate others on the importance of trying to ask at least one thought-provoking question when a JW is at your door. At least be kind, if you can't do anything else.
Approaching JWs in Love by Wilbur Lingle and Captives of a Concept by Don Cameron have been especially useful. I also used the information in Sky Man's Blood Letter (Does anyone know where that is? I got it here.) very effectively. I can tell you how, if it is something you would like to find out more about. Just PM me!
Whatever you do, don't ever give up. Don't hammer it constantly either, but never, ever give up. Keep your relationship in good standing. YOU may be the only one who will ever have the love and determination it takes to help them find their way out of the burning building.
Whyizit