A 3-year-old boy whose aunt allegedly pushed him off a pier into Lake Michigan last week has died, the Cook County Medical Examiner’s Office said Sunday. Victoria Moreno, 34, is accused of shoving Josiah Brown into the water on Sept. 19, then standing there without helping as the toddler struggled for his life. The child was rescued by divers about 30 minutes later and was rushed to the hospital. Moreno told police that Brown, who was known as “JoJo,” according to a fundraiser set up by the boy’s godfather, had been “acting up,” the Chicago Sun-Times reported, citing an unnamed source with knowledge of the investigation. In court, a lawyer for Moreno, who remains detained without bail, argued for leniency, saying she is mentally ill.