Please recommend a novel. Did the female lead lie to the male lead in order to get him to donate his bone marrow to her brother?

In order to save her brother from leukemia, the female protagonist went to the male protagonist. In order to save her brother from leukemia, the female protagonist went to the same school as the male protagonist. The male protagonist knew the purpose of the female protagonist and said,"I won't give you a spoonful of bone marrow." However, he still saved his brother. In the end, the male protagonist left the female protagonist and also got leukemia. It was a novel I read a few years ago. I really can't remember what it was called. I'm looking for the name of the novel.