Character Analysis
The first thing we learn about Tayo's cousin Rocky is that he died during the war. He and Tayo were very close—like brothers—and Rocky's death is the culmination of the tragedy that Tayo experiences as a soldier. Tayo felt responsible for keeping Rocky safe. It's because of Rocky's gangrenous wound that Tayo curses the jungle rain, which results (he believes) in the drought. So Tayo feels immensely guilty when Rocky dies.
As a teenager, Rocky is critical of Laguna "superstition" and prefers the scientific lessons taught by the white teachers at school. By the standards of these well-meaning whites, Rocky is poised for success—if only he can avoid being held back by his community's primitive traditions. He gets a football scholarship, and the whole family is excited and proud that he'll be the first to go to college.
Rocky's devotion to white culture and his belief that white society is more progressive and prosperous than Laguna society leads him to sign up for the army. Rocky's death, therefore, is a particularly harsh indictment of white culture, which, for all its innovation and progress, can only lead to destruction.