Thanks for your answers! How about this story? I didn't really change it very much, but I added more details.

A girl has headaches, vomiting, and memory loss. Her dad takes her to the hospital. They do an MRI on her brain. They find out it's Meningioma, a type of brain tumor. They say there's never before been a case where the symptoms were so acute for such a big tumor. It's so big they know they can't get it out. They decide to leave it and give her 3 weeks until she should come back and die because it won't affect the time she has left of her life. 3 weeks later she goes to the hospital and passes away.