Dr. Gil Beltran was for many years the owner and Director of the Colegio La Luz in the Vedado neighborhood of La Habana, which I attended.
Here is a short biography from the school's alumni paper:
Dr. Gil Beltran Cuesta was born 19 Dec 1905 in Cardenas, Matanzas, the second son of his parent's. His family moved to Habana in 1914 and he was sent to study in the Jesuit school in Gijon, Astruias, Spain. He started teaching at the Colegio Belen in 1923 and alto taught in the Instituto de La Habana. He married Estilita Gonzalez, from Jaruco, and had two sons Paki and Fabian. In 1945 he purchased the Colegio La Luz, with financial help from his in-law Ramon Luzarraga. In 1961 the school was taken over by the FEU and Beltran requested asylum in the Venezuelan embassy and left for Miami. He taught in Mountain Lakes High School in New Jersey till 1970, when he returned to Miami to reopen the La Luz School. His wife Estilita died in 1978 and Dr. Beltran retired in 1992 after 69 years of teaching. He celebrated his 90th birthday in Miami in December of 1995. In 1997 the school's alumni paper reported that he was ill so I doubt if he is still alive. Unfortunately, that paper ceased publication so I have no more recent news.