Highet's older brother, William Bremner Highet, was an Otago University scholar and professor of neurosurgery, who died when the  was sunk in 1942. Highet's uncle was Harry Highet, the civil engineer who designed the P-class sailing dinghy.
William Bremner Highet, the older brother of Highet, studied at Otago University and taught neurosurgery there until his death when the ship he served on was sunk in 1942. Harry Highet, who designed the P-class sailing dinghy, was Highet's uncle.