How can this be done on FACEBOOK

She has set her privacy settings as strictly as they will go.

Just because she has unblocked you doesn't mean it changed her privacy settings on her page, especially if you aren't on her friends list.

I have the privacy settings on my page so that only my friends can see the content. If you aren't on my friend's list, all you see is my photo and any posts I made with a "public" privacy setting.

If you are on her friends list, then she probably hasn't unblocked you or she has her privacy settings set to "only me" so no one no matter who they are can see anything she puts on her page unless she intentionally changes the privacy setting for a specific post.