Jupiter Rising - Gary D. Schmidt

When Jack's P.E. coach pairs him up with Jay Perkins for the cross-country team, neither of them is happy about it. Jack is grieving the loss of Joseph, his foster brother, and adjusting to his role as big brother to Jupiter, Joseph's orphaned daughter. Dealing with Jay Perkins-who'd once ganged up with his buddies to jump Joseph in the locker room-is the last thing he wants to do.
But then Jack realizes that Jay is grieving too-the loss of his cousin Maddie, Jupiter's mom.
As Jack's relationships with both Jay and Jupiter grow and his running improves, he starts to feel more like himself than he has since Joseph died. He's finding his stride . . . until Maddie's parents, who have never shown interest in their granddaughter before, decide to claim Jupiter as their own, blocking Jack's family from adopting her.
And suddenly Jack's past and present smash together, threatening to dissolve both his newfound confidence and his friendships.
This poignant, powerful companion to Orbiting Jupiter is Gary D. Schmidt at his best. He is the author of the Printz Honor and Newbery Honor Book Lizzie Bright and the Buckminster Boy; Okay for Now, a National Book Award finalist; and The Wednesday Wars, a Newbery Honor Book, among many acclaimed novels for young readers.