Final answer:
The title 'Sonny's Blues' is an allusion to both the blues music genre and to a deeper emotional state, reflecting the thematic mood of the story. Sonny's character is misrepresented by his brother, who fails to understand him, but a moment of reconciliation occurs when the brother attends Sonny's concert.
Step-by-step explanation:
Allusion in literature is a reference to another piece of work, a historical event, figure or cultural context, which can add deeper meaning to a text. In the case of the title "Sonny's Blues," the allusion is likely a reference to the musical genre of the blues, as well as to the mood of the story, hinting at a deeper layer of sadness or melancholy that exists within the narrative. The blues as a musical genre often express the struggles and emotional pain of life, thus providing an insight into the character's experiences and the overall theme of the story.
The misrepresentation by Sonny's brother can be interpreted on multiple levels. It involves both a failure to understand and appreciate Sonny's life experiences and ambitions and perhaps a projection of his own fears and prejudices. The brother's attendance at Sonny's concert at the end of the story symbolizes a moment of reconciliation and understanding, signifying that he has finally begun to see Sonny outside of his own misconceptions.