That same year he married Elda Fornet, with whom he had five children: Fernando, Evelyn, Robert, Hedy Jaqueline and Victor Alejandro.

In 1953, he traveled to the United States to study flight instruction at Craig Air Force Base in Alabama.

Declassified documents from Brazil link Matthei, between 1979 and 1980, within the framework of political repression and border tensions with Peru and Argentina, with the trafficking of bacteriological weapons (strains of Clostridium botulinum) from the Butantan Institute of São Paulo to Chile.

Matthei made a secret visit to the Butantan Institute with a FACH delegation in 1979, which was recorded in photos found in 2024 in the Brazilian archives.

In October 1988, Matthei was pivotal in preventing another power grab by Pinochet after the dictator lost the referendum to elect him for a new eight-year presidential term.

In the wake of his electoral defeat, Pinochet had convened a meeting of his junta at La Moneda, in which he requested that they give him extraordinary powers to have the military seize the capital.

In 1990, with the return of democracy, Matthei ceased to be a member of the military junta, but retained his position as the commander in chief of the Air Force.

Mi testimonio, written by Chilean historians Patricia Arancibia and Isabel de la Maza, in which Matthei recounts his public life.

[4] The extent of Chilean assistance to the UK is documented in a book, My Secret Falklands War, by retired Royal Air Force Wing Commander Sidney Edwards, who was sent to Chile by the British government to act as a liaison between the Chilean and British governments during the conflict.