Mourning Song

You don't know me, but I know about you.... I  can't make you live longer, I can't stop you from  hurting. But I can give you one wish, as someone did  for me.
It's been months since  Dani Vanoy's older sister Cassie has been diagnosed  as having a brain tumor. And now the treatments  aren't helping. Dani is furious that she is  powerless to help her sister, and she can't even convince  her mother to take the girls on the trip to  Florida that Cassie has always longed  for.
Then Cassie receives an anonymous letter and  check. Dani knows she can never make Cassie well, but  against all odds she dares to make Cassie's dream  come true.
From the Paperback edition.