In the section "Drown," the narrator frequently reminisces about his adventures with his former friend Beto. The narrator, who I assume is Rafa, seems to miss the old times with Beto, even though they've grown apart.
In one section, from page 97 to page 99, the narrator remembered stealing from the mall he went to with his mom. The narrator and Beto stole from the stores without getting caught most times. Although the boys' attack strategy seemed to work, the narrator seemed more afraid to get caught as time went on, especially when his father started to notice all of the stolen clothes that had been collecting in the narrator's bedroom. The narrator's father knew that the narrator was getting a lot of new stuff without holding a job. On the other hand, Beto got cockier, like when he talked to the security guards before he and the narrator left with their loot.
In the final story that the narrator talked about, he seemed more internally nervous when he and Beto tried to escape. He tried to walk away and pretended to act annoyed when the old woman confronted them, but Beto became rude and beat the old woman up with the bag of stolen goods. When the security guard finally caught the boys, the narrator started crying, but Beto didn't. In that respect, the narrator didn't show the machismo quality, since he cried out of guilt and fear. This example of the lack of machismo leads me to believe that the narrator is Rafa because he acted manly and stole stuff with his friend, but acted guilty and started being "girly" and crying when he and Beto were caught.