The before-mentioned Steve Hassan really promotes talking about OTHER groups that have similar practices. That way she might consider the problems without the mental walls going up. Like...
"You know, I heard Scientology leaders have their followers install software on their computers that block everything about Scientology on the internet... why do you think they do that?" Create scenarios where she formulates the answers in her own head. The next time the WTS rants about avoiding the internet it might give her pause.
"Hey, I was just reading about the Mormons. Did you know their leaders claim to be God's modern-day prophet? I also didn't know they claim to be the only true religion did you?... the members even call their religion "The Truth"! Wow, that's interesting."
Do it more artifully than I just did and DON'T follow it up with "JUST LIKE THE JWs!!!" It's up to you to innocently phrase the question so she makes the connection herself. Oh, & you have to do it in a way she can't figure out what you're doing. Good luck.