13 Reasons Why: All the Characters We've Lost Since Season 1

After Justin collapses during the high school prom in season four, a doctor reveals to Clay and his parents that Justin has tested positive for HIV-1, and based on his symptoms, it has progressed to AIDS. Though the hospital does its best to manage his symptoms, his doctor reveals that he has developed a disease in his lungs and they're already starting to see advanced neurological symptoms. A week or so later, his doctor reveals that his brain infection is "advancing quickly" and gives them a few hours to say their goodbyes. Following an emotional talk with Jessica and Clay, Justin dies in his hospital room.