A fellow poster privately asked me this question. It's a great question and I thought it was worthy of a public response, so here it is.
Q..my best friend has been studying with [the JW's] for 9 yrs. Not baptised yet, but heading that direction. I've been trying to learn as much as I can and prepare myself to present "thought-provoking questions" whenever I can. Trying to prepare myself for all the rebuttals also. It's a never ending process! I am curious as to what kind of success you have had in breaking the mind control that the WTS has over your husband?
A. If your friend has been studying for nine years, I think they are well past being easily turned from the WTS. A well-laid argument won't do the trick Within three weeks of a new study, a JW will have primed the person for "opposition". And this "opposition" they are told, is directly from Satan!
Becoming a JW takes a lot of time and study. Even if the study starts to doubt, their natural tendency to avoid dissonance (how could I have been so stupid?) will encourage them to be resolved to stick it out. Read up on cognitive dissonance to better understand this phenomenon. http://www.learningandteaching.info/learning/dissonance.htm
On the plus side, if it has taken nine years for your friend to make up his mind, there may be something holding him back. Does he smoke? If so, the JW's will insist he quit first. If it's not a secret sin holding him back from baptism, he may indeed harbour secret doubts about the organization. You may be able to smoke this out by asking some leading questions like, "Is there anything that would convince you that they don't have the truth?"
Never ending process indeed! I've been at it for five years, with no end in sight. It seems a JW goes through cycles of devotion, and that there are two distinct personalities inside them. One is the person you know and love, and the other is the "put on" cult personality. Steve Hassan suggests making peace with the cult personality, and coax the natural personality in to the open as much as possible. So again, doctrinal arguments with the "cult personality" are pretty useless. They just end up digging themselves in deeper. I suggest also that you purchase Steve Hassan's "Combatting Cult Mind Control" http://www.freedomofmind.com/
How do you coax out the natural personality? Reminisce of times together. Talk about their hobbies and interests. Ask about their childhood, their hopes and dreams. Tease them about some quirk in their nature that makes them uniquely them. Reward independent thinking, and always honor their choices. I notice the natural personality comes to the fore the longer away they are from the witnesses, so if you can get them to take a break from a regularly scheduled meeting, that's great! The cult personality starts to take hold again about eighteen hours before the next meeting.
As for thought-provoking questions, I suggest bringing them up when the natural personality is at the strongest. Bring up the thought or idea, and if they show any anxiety, quickly drop it. You've done your job, you've planted the seed.
With practice, you will be able to spot the cult personality in the expression of your friend's face and their manner of speaking. The face literally becomes rigid, the words robotic and staged, straight out of the magazines. It's a scary thing to see the first time.
I suggest also if your friend gets baptized, to go along for the view. Bring your camera. Chat about what you see in the assembly and your honest impressions of the baptism ceremony. And plan ahead to take him out to dinner to celebrate afterwards. That will deflate the glamour from baptism, which is supposed to drive Satan's minons mad.