 While helping Donnie train, Rocky is diagnosed with non-Hodgkin's lymphoma.He is unwilling to undergo chemotherapy, remembering that it was not enough to save Adrian when she had ovarian cancer.His diagnosis and the fact that his best friend and brother-in-law Paulie Pennino—Adrian's brother—has now died in addition to Adrian, Apollo, and his old trainer, Mickey Goldmill, further force him to confront his own mortality.