Hey Rotolutundro,
sounds like you'll need to address this out of game,
share with her that you are trying really hard to help her invest her character in the story and you feel like she is not responding,
Trying to fix this in game will possibly cause further frustration for you and her, but explaining what you are trying to do will at least open up channels of communication.
Also ask her what being involved would look like for her, how she would like you to incorportae her, etc...
