As a result, his grades are dropping. He's very talented musically and loves the creativity that he finds in music. Unfortunately, he has concluded that none of that same creativity exists in math. The reason is that many math problems are not easily related to the 'real world'. In contrast, it does not seem to follow from the original message that the boy got to appreciate music because of the creativity inherent in its applications in the real world.
Music has a unifying and uplifting effect on listeners.
It's not spelled out explicitly what creativity the boy found in music. He might have discovered a gift for creating music, or felt an excitement of his uniquely personal rendering. I do not know. Mathematics is often compared to art. In an assay on Humanistic mathematics , Philip Davis likens mathematics to literature.