Seven years ago, Mike Moore stepped from the 2 a.m. darkness into the light of a small home off Lakeland Drive in Jackson, Miss., to find his nephew close to death. The 250-pound 30-year-old was slumped on the living room couch, his face pale, breath shallow, and chest wet with vomit. It was his fiancée who’d called Moore, waking him in a panic. Now they were both screaming in the man’s ears, dousing him with ice cubes and water, and pinching him as his respiratory system began to collapse.

Moore had become familiar with the signs of an overdose since his nephew, for whom he’s a father figure, filled his first legal prescriptions in 2006 for Percocet, an opioid painkiller made by Endo Pharmaceuticals Inc. By 2010, his nephew, who asked not to be named, was obtaining generic fentanyl on the street. Another synthetic analog to the opium poppy, fentanyl—the drug that killed Prince—is as much as 100 times stronger than morphine. The night of the overdose, Moore’s nephew had been wearing a fentanyl patch on his arm and sucking on another. “An ordinary horse would have been dead,” Moore recalls in his Mississippi drawl.

Related: CDC: Opioids are a last resort