I am so sorry to hear that.
One of my best friends lost her father to brain cancer a few years ago and her family put together a foundation in his honor. I know everyone has their own way of dealing with news like this, but if you are the type to find comfort in learning all you can about it or in joining a community, maybe you would like to visit
their website.
Keep your chin up and show her your love while she's still here.
*HUGS*