Even when it comes down to child abuse, she brushes it off. Everything.
That's what brainwashing looks like. However, it might seem like it's not having any effect on her, but it might. If you look at a lot of people here, what opened their eyes are very different things. Some people start thinking more critically when there's too much that doesn't make sense, others when they feel shunned and don't see any benefit in remaining loyal to that organization, and some others for some other reasons.
I'd say stay in conversation and don't have any expectations of her reaction being different than what you have experienced so far. She is paying attention, her curiosity may awaken by something you say at some point. Please keep in mind that what woke you up may not be what does other people. They are blindly following that organization and conditioned to feel that such blind devotion is ok.
Have you tried asking her things, instead of always pointing things to her and telling her things? If you don't know the real reasons why she's in that organization, you might be missing what you should address. As much as they claim that they are all the same "sheep", they are human beings with their own thoughts and their own diverse reasons to be there. Address her individual thoughts and reasons to be a JW.