Complex sentence: James Lunika, who was very close to Khotso in the 1960s, believes that Khotso's clients probably did experience something very frightening, because such tests made good business sense.
Split into simpler sentences: James Lunika, who was very close to Khotso in the 1960s, took a pragmatic view. He believed that Khotso's clients probably did experience something very frightening, because such tests made good business sense.