In 1954 he married Spanish domestic worker Leonor Corbacho Velasco, a young lady from Valverde del Fresno (Cáceres).

Holmes could communicate with the animals by means of eye signals and barely perceptible head movements which he would use to stop them from taking food offered to them by tourists.

He would also take sick or injured monkeys to the Royal Naval Hospital where they would receive the exact medical treatment as an enlisted soldier.

Holmes' time in the job made him an authority on this group of Barbary macaques, with his knowledge being sought by various scientific studies on the monkeys from around the globe.

[1][4][7][8] In the early 1990s, Holmes was diagnosed with esophageal cancer, later traveling to London to undergo major abdominal surgery.

His body now rests in a family grave together with his father, grandfather and various half siblings at North Front Cemetery, Gibraltar.