I'm so sorry about this.
Your family is in my prayers.
I'm a 14 year old, and all most of us want for Christmas this year is somewhat expensive stuff haha. I would say you can't go wrong with a gift card to the mall. And also if she has any special interests, get her something that has to do with that. I don't really know what I want for Christmas, so I'm not much help. Sorry.
Best of luck to your family.