In the three months I spent talking to friends and family after I realized that the "Truth" was anything but, I learned that this is the last thing a JW says before shutting off his brain entirely.
For me, it usually worked like this: JW tries to find common denominators such as faith in the Bible, belief in God, etc. If this fails, he tries to convince you of those fundamental points. After you make logical points overturning each of his arguments, he switches to, "But this is God's organization" mode. Various "evidences" are brought forward, such as supposed unity, worldwide preaching, etc, etc. When each of these is handled and shown to be insubstantial, JW is not left with much else. However, surrender is not an option.
The only possible endgame for our beleaguered JW at this point is to profess his faith in unassailable terms - namely, that even if everything he said previously were false, he would still believe because [insert reason]. The reason I got was usually "I have good friends, I'm a good, honest person - hey, even if it's not the Truth, I've still lived a good life." I always marveled at how defeatist that sounded. I had a 22-year old kid say that to me. I said, "Geez, you sound like a man committed to the gallows."
To such people, one can only say, "I'm pretty much like you, except my position is that if it isn't the truth, I cannot believe it."