He is buried to a family grave in the Koomankangas Cemetery in Kokemäki. Horelli was married with Lempi Josefina Lehtonen (1889–1967) in 1917. The couple had two children. His brothers were the professor Väinö Horelli (1882–1973) and the physician Edvard Johan Horelli (1871–1946) who was interested in eugenics.