The original question had to be edited. I think that Johnny Corazon, literally meaning "heart," plays a therapeutic role in the novel. He seeks to deliver treatment that is not necessarily traditional, but holistic in its purpose. He seeks to broaden the binary divisions that define D.Q., but also define Pancho. D.Q. might not necessarily have to "choose" between "life and death." Through Johnny Corazon, there might be a way to experience healing in a sense that prepares the way for death, a way to die with dignity and understanding as opposed to the chemotherapy that kills everything in D.Q.'s body- both healthy and unhealthy cells. At the same time, Johnny is open about how his therapeutic ways might serve Pancho, as well as D.Q. When Johnny tells Pancho that this might be "for his benefit, as well," it illuminates how Pancho is a form of the living dead. Pancho is so consumed with revenge and anger that it is eating away at his being. The very life that D.Q. yearns for is something that Pancho is willing to throw away. His treatment plan involves rituals and holistic medicine that is in stark contrast to the chemotherapy that D.Q.'s mother insists he endure.
Yet, the more therapeutic element of what Johnny Corazon performs is the change in Pancho. He becomes more understanding of what life is and what it means to identify himself with something more than himself and his anger. It is in this where Johnny has performed some healing. While Pancho's embrace and maturation can be attributed to many ideas, Johnny recognizes that his form of treatment "might be for his benefit" as well as D.Q.'s. As there is change in Pancho at the end of the narrative, one can see that the holistic embrace of healing has effects that extend to D.Q. and beyond him to Pancho. In Pancho finding his own "heart," Corazon's healing methods have been felt.