The Boy with a Smile — Megan Davidson

After her half brother moves in with her and her dad, Katrina Maccini notices something about him that is strange and almost irritating: Alex is always happy. Always! And he's nice to everyone, too. It just doesn't make sense. Alex's own mom died, so he has to live with the man who left her and the same guy's daughter who, frankly, is really snotty. But he's still the bright star in the house! Katrina is determined to put an end to his rainbow presence and a dimmer to his too-bright spirit, but instead she may end up learning something from the boy with a smile.