Fretes was born in Santa Elena, Cordillera Department, Paraguay, on 14 February 1915.
Fretes enlisted in the Paraguayan army during the Chaco War (1932–1935). In June 2023, at the age of 108, he remained lucid, recalling his experiences during the war. According to his granddaughter, he would often reminisce about the battles against the enemy, describing how they dug holes for refuge underground. He never forgot that during that time, they suffered from thirst due to the lack of hydration options, enduring days under such conditions. However, they managed to sustain themselves by consuming fish for food.
At some point, he had two children: Juan Heriberto and Lucila.
At the age of 108, he was still able to walk extensively with the assistance of a cane. His granddaughter commented that the family attributed his good health to his childhood diet, which primarily consisted of fish, milk, and corn. She added that these were his sole food options, as there were no alternatives available at the time.
Fretes passed away in Santa Elena, Cordillera Department, Paraguay, on 5 July 2023, at the age of 108 years, 141 days.
At the time of his passing, he was one the oldest (documented) living residents of Paraguay, as well as one of the oldest living veterans of Chaco War.
* “Excombatiente con 108 años de edad goza de muy buena salud en Santa Elena” – ABC Color, 8 June 2023
* “A los 108 años murió el último excombatiente de la Guerra del Chaco de Cordillera” – ABC Color, 7 July 2023