Confuzzled, it's understandable that you don't want to become the WTS's worst enemy. All you want is your witness out. I know that reading all those books, reading all the boards, et cetera, takes precious time which, in the end, you would want to use otherwise, since the witness in question can't seem to even be remotely interested in a little eye opening. I bought something like nineteen books and have read many, but not all, and I know I have months of reading time ahead of me. My witness already pushed me away, and, though I know I might see her again, I know I won't have much chance to influence her mind. But, I haven't given up hope. Who knows, one single line and they might just start thinking. If someone offered me to trade six months of my time for getting her out, I would do it.
In your case, it's a personal decision whether you want to keep reading or not. I think I will, because I'm liking what I read. The original purpose is now a distant second.
I see you're making a mistake with your witness. You're talking to him about the WTS. The minute he hears something, he will enter stone-deaf denial mode and won't really listen to anything you say. You have to plant seeds about other religions or other people, so he connects the dots. He can push you away but he can't push himself away.
I really wish you the best. I'm not sure what the best is.