The Top of the World by Ethan Joella
This is a sad but beautifully written book about making the most of the time you have. The story is set in the 1970s. Chip is the golden boy, beloved by all. Maggie is his sister, a year younger and more of a quiet soul. Chip is dying of leukemia. He figures he has one summer left and wants to spend it somewhere that doesn't involve hospitals and doctor visits. So he takes off for a resort in the Poconos and gets a job there. After he dies, Maggie goes to the same resort and gets a job to find out more about her brother. The story alternates between their 2 adventures at the Red Maple Inn. Highly recommended.