Hubert van Klyk is referred to in the text as a "millionaire hermit." Based on the illustration depicting him, he appears to be a Hindu swami. Hindu swamis were a common pop culture icon during the 1960s when this story was first published. During this time, many people, particularly members of European and American intelligentsia, including wealthy nominal Christians and pop icons such as the Beatles, flocked to swamis for spiritual advice or in search of new and novel experiences.
Hubert van Klyk is clearly Causasian, with a European (pseudo-Dutch?) name. He is presumably a convert to Hinduism, or to a swami-taught spiritual path derived from Hinduism, even if it is not overtly named as such.
From: "Perry White, Cub Reporter!", originally presented in Superman's Pal, Jimmy Olsen #42 (January 1960), pages 4-5; written by Robert Bernstein, pencilled by Curt Swan, inked by John Forte; reprinted in Superman: The Daily Planet (DC Comics: New York, 2006), pages 30-31: