Gabriel Márguez and his friendship with Fidel Castro is very puzzling as Márguez did support Castro ideas however their relationship is not just Márguez supporting and producing propaganda in form of his novels. It is more of a workers friendship as Castro helped Márguez edit his books so that the grammar and facts were correct. The following quote explains Castro and his work on Márguez book:

Castro’s corrections were factual and grammatical rather than ideological, she added. “After reading his book The Story of a Shipwrecked Sailor, Fidel had told Gabo there was a mistake in the calculation of the speed of the boat. This led Gabo to ask him to read his manuscripts … Another example of a correction he made later on was in Chronicle of a Death Foretold, where Fidel pointed out an error in the specifications of a hunting rifle.” Elsewhere, Castro offered advice about the compatibility of bullets with guns used by García Márquez’s characters.

Castro and Márguez worked together on the final stage of editing his novels, which indicates even though Márguez did support his movement and ideas, their unusual friendship was not just about Castro ideals, it was also about Márguez and the things he was writing about and literature. The friendship was based on their love of literature and not political views. Which is not Castro was known for.

https://www.theguardian.com/books/2016/dec/06/fidel-castro-worked-on-gabriel-garcia-marquez-manuscripts