She needs to come out of this on her own. You may be able to plant some seeds such as others have recommended. But you really need to back away, explaining this very thing to her. She must dig deeply within herself to gather the strength of character to leave the abusive relationship on her own terms.
I know you probably don't want to hear all of this even though you did ask. You have to understand that we have a great deal of experience with the JWs and we can see that if you pursue this as you are, you are just asking to be hurt deeply and are not doing the woman much of a favor either.
If she comes out of it, on her own, she'll be a better person for it and you'll have a better friend for it as well.