Chiisana Kimi to, Koe wo Tooku ni

Former vocalist of a popular band, Fujinami Souta, and Shirase Sora, a fifth grade elementary school student. A boy who has given up on his dreams, and a girl who is pursuing her own. The meeting between the two moves Souta's stagnant heart, and he begins private lessons to help Sora's dream come true.

(Source: Shounen Sirius, translated)