Cook County Medical Examiner's office confirmed that the 45-year-old musician died on Saturday, reported Chicago Tribune.
Fuentes was in a car in the 4300 block of South Archer Avenue after celebrating his birthday with friends and colleagues when someone walked up, showed him a gun and told him to get out.
When he wouldn't get out of the car, the gunman fired multiple shots, hitting him in the head.
Police initially said the man had been pronounced dead soon after the shooting, but he was placed on life support so relatives could arrive from Mexico, according to family and friends.
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He opened a performing arts studio in Brighton Park called Tras Bambalinas, Spanish for Backstage, which taught young people singing, dancing, acting and modeling. He was shot on the same block as the studio, which also served as his home, according to records.
Since opening Tras Bambalinas, Fuentes has been a regular at Mexican-American cultural events, staging elaborate costumed musicals as he taught youngsters the fundamentals of performing arts and entertaining.
The attack comes less than a week after the killing of Christina Grimmie, who appeared on the US version of "The Voice".