"Kids can get hungry sometimes while on chemo," says five-year-old Sammy, having a good day despite the malignant tumor invading his brain. Based on true events from the 1980s, Sammy's story is imagined by his mother and brother as if the young boy might tell it himself. The result is gripping. Told in two parts, Sammy's account first invites us into the everyday middle-American lives of a mom and her two boys. Sammy is a sweet, good-hearted kid,...