Jesse's parents called an ambulance about 1 a.m. when his heart stopped beating, one of the family's lawyers said. Attempts were made to resuscitate him but were unsuccessful, and he died at 1:28 a.m.
"They [the parents] indicated they were very saddened by the death of their son but also at peace," attorney Stacey Schmidt said at a news conference late Friday. "They were glad other members of the family got an opportunity to come to Utah and say their goodbyes."
The boy, who was on a ventilator after slipping into a coma earlier this fall, had been at the center of a treatment disagreement between his parents and Primary Children's Medical Center.
Doctors said Jesse, 6, was legally brain-dead and wanted to remove him from life support in mid-October. His parents, Steven and Gayle Koochin, of Florida, obtained a court order preventing the hospital from disconnecting him from the ventilator.
The Koochins took their son home to a Salt Lake City-area apartment two days later, where they cared for him with the help of hospice nurses, a doctor and a ventilator.
The couple came to Utah in September seeking alternative treatments for Jesse, but he had trouble breathing and was admitted at Primary Children's.
Gayle and Steven Koochin, who were outspoken in the beginning and shared Jesse's medical records with the news media, have asked for privacy since they brought him home. Their other lawyer, David Pace, issued a brief statement on Friday thanking the public for its support.
"The Koochin family appreciates the opportunity they have had to spend the last month bringing their family together and caring for Jesse . . . They are grateful that they have had the chance to make decisions concerning Jesse."
The Koochins had reported seeing positive signs from Jesse. His mother said he responded to massage and that he could move his feet. His parents were giving him herbal treatments, Schmidt said.
"I think the care he was receiving at home was much better" than at the hospital, she said.
Doctors had predicted that Jesse's condition would worsen, saying his body actually had begun to decompose. They also believed his heart would stop even with a ventilator.
The controversy over Jesse's condition and care leaves many unanswered questions.
Schmidt declined to say whether the parents and Primary Children's have any ongoing legal disputes.
Although Primary Children's agreed not to file a death certificate for the boy during a court hearing on Oct. 27, hospital officials say they will not care for brain-dead patients meeting Utah's legal definition of death in the future.
The murky question of what should be done when parents disagree with a doctor's determination of death remains. There are no laws saying doctors have to keep patients they believe are dead on life support.