The One in a Million Boy by Monica Wood

 

The one in a million boy is a quirky, smart, awkward boy who volunteers to help 104-year-old Ona Vitkus around her house, in pursuit of a Cub Scout badge. The two become fast friends and he starts taping interviews with her as she recounts her long life. Then one day he doesn't show up. Instead his father, Quinn, does, offering to complete the rest of the boy's service. He doesn't tell her, but the boy has died from a heretofore unknown heart ailment. The boy's mother, Bella, is devastated. Quinn, a musician who has spent less time with him,  isn't sure what he feels. But the more time Quinn spends with Ona, the closer he feels to his son. And the very last scene, where we learn how much the boy loved his father, will bring a tear to your eye.