A Thousand Broken Pieces - Tillie Cole

Three years. Twelve months.
A timeless grief.
After losing her beloved sister three years ago, Savannah Litchfield has been living half a life. Now seventeen—the age Poppy died—the pain of losing her is worse than ever. When Savannah's therapist suggests a trip around the world to help teens stricken by loss, she reluctantly agrees to it, clutching the unread journal Poppy left her as she goes.
Cael Woods is angry. One year after losing his older brother—the person who meant the world to him—his life has spiraled into a heady void of nothing. Once the most promising hockey player in the junior league, Cael can no longer step onto the ice without being paralyzed by memories of his brother. When his parents sign him up for a trip abroad for grieving teens, no part of him wants to go—but he does.
As Cael and Savannah embark on a journey of healing, they learn to find solace together, discovering a glimmer of light only the other can bring. And the harder they fall, the more they heal the fractured fragments of their hearts, piece by broken piece.