Camp Resound by Christine Isley-Farmer

Nana Weathers, Chloe, Shannon, and Boomer head to summer music camp. There, they unexpectedly find Peanut, a dog they met at obedience school who was a bully. Peanut's human, Jack Hunter, a violinist, serves as counselor and lifeguard. Chloe, Shannon, Nana Weathers, and Boomer make friends with young Carlos Garcia. Carlos doesn't want to be at Camp Resound, because some not-so-nice kids tease him. Can Carlos's newfound friends help him have a different experience than he expected, and will Boomer and Peanut find a way to bury the bad bones between them?