what sacrifces does Jimmy make and whether or not they had a positive or negative effect

Jimmy is Lisamarie's younger brother. His disappearance is the catalyst for Lisa's series of recollections and journey to Monkey Beach. As children, Lisa and Jimmy are close and often play together. But their paths begin to diverge as they grow up, with Jimmy becoming invested in his studies and swimming, while Lisa resigns herself to being an outcast. Jimmy also does not experience the same supernatural abilities as his sister, which contributes to the distance between them. For this reason, Jimmy remains a character on the periphery for much of the narrative. It is not until Jimmy faces his own personal setback—dislocating his shoulder and being forced to quit the swim team—that he and Lisa become close again. The siblings mutually help each other regain a sense of stability after experiencing great hardship. His fate at the end of the novel is not revealed. What sacrifices that Jimmy makes help him become closer to his sister which seems like a good thing.