The Rules of Rain by Leah Scheier (2017)
Rain has taken care of Ethan all their lives. Before she even knew what autism meant, she was her twin brother’s connection to the world around him. Each day with Ethan is unvarying and predictable, until one night when her world is turned upside down by a mistake she can’t take back. As her new romance with her longtime crush and her carefully constructed life begin to unravel, Rain discovers that the fragile brother she’s always protected has grown into a young man who no longer needs her. And, for the first time, she discovers just how much she needs him.
Publisher: Sourcebooks Fire
Reading Age: 14-17