All the Broken Pieces by Ann E. Burg

Two years after being airlifted out of Vietnam in 1975, Matt Pin is haunted by the terrible secret he left behind and, now, in a loving adoptive home in the United States, a series of profound events forces him to confront his past.

Matt must go through tremendous termoil to find where he truely belongs. He must rediscover what it means to be a little boy. What it means to be himself. He will go head to head with veterans who fought for his freedom, and bullies who lost their family members. But yet, he never gives up. Ever.