While my youngest brother was in his last few months of life prior to being taken by Leukemia, some family members (including him, actually) had their hopes variously set upon one or another kind of miracle. I never argued with any of them, I just stuck close to my brother while letting him know I would walk with him to the end while helping him in any way I possibly could along the way. If you have direct contact with the daughter, just "be there" for her and try to be helpful and supportive of her without getting into anything about what anyone else might be thinking or saying. And if you are someone who prays, you can let her know you are praying for her daily without getting into the specifics of your actual prayer. For my brother, I simply prayed he be given strength to endure to the end of his bout with cancer.