Hours after doctors declared three-time world champion Hector "Macho" Camacho brain dead after being gunned down in a car, the fallen fighter's son said they would keep him on life support.
"It's up to God," Hector Camacho junior, known as "Machito" said of the family's refusal to turn off his ventilator, despite medical pessimism.
Camacho junior arrived in Puerto Rico on Thursday afternoon and immediately headed to his stricken father's bedside at the hospital where he has been treated since being shot in the neck on Tuesday.
"Papi was a great fighter, a warrior and now he is fighting for his life and we have to let him fight until the end," he said.
Dr Ernesto Torres, director of the Centro Medico hospital in Rio Piedras, Puerto Rico, said earlier that Camacho had showed no sign of brain activity.
"Clinically, Hector 'Macho' Camacho is brain dead," he said, adding that it was up to the family to decide whether to disconnect the respirator that is keeping the former boxer alive.
The announcement came some 30 hours after Camacho, 50, was shot while in a car in San Juan outside a liquor store. The boxer's driver, Alberto Mojica Moreno, 49, was killed in the shooting.
It was not immediately clear if they were deliberately targeted or simply caught up in a random act of violence. The bullet damaged three arteries in Camacho's neck, crippling the flow of blood to his brain.
Camacho, originally from Puerto Rico, was one of the most colourful boxers of the 1980s, winning world titles at super lightweight, lightweight and light welterweight.
With a career record of 79-6-3 with 38 knockouts, he took on all comers, including big names Oscar De La Hoya, Julio Cesar Chavez, Sugar Ray Leonard, Felix Trinidad, Ray Mancini and Greg Haugen.
But earlier this year, US police charged him with child abuse for allegedly slamming his son into a floor at his ex-wife's home in Florida.
The incident took place on March 22, 2011, allegedly a dispute over money Camacho believed was missing at his ex-wife's home, police documents show.
In recent years, Camacho has made appearances on two reality television programs.
Puerto Rico's secretary of recreation and sport, Henry Neumann, meanwhile, has offered to help the family arrange funeral services if required.