These questions help to focus attention on the narrator’s brother’s ambitions. Sonny explains that playing jazz is “the only thing” he wants to do[9]—the only thing that excites and compels him enough to keep him away from more destructive forces, namely heroin. His brother is opposed to the idea because it’s an incomprehensible one to him. To commit to playing jazz would be to commit to a whole life of improvisation, not just in musical terms but in the larger terms of employment and futurity. The narrator wants to be able to rest knowing that his younger brother, who already has a criminal record and drug conviction under his belt at age seventeen, is safe. He does not want to suffer through years of watching Sonny improvise his way through the world.