Sullivan separated from his first wife in 1921, and married Vere Bartrick Baker in October, 1928, with whom he had a son, Navin (born in 1929). Other sources believe Sullivan married Nursing Sister Jessie McNoegh at around the same period, with whom he had a son Patrick Evelyn John Sullivan (born in 1929). In the early 1930s he was increasingly troubled by bad health, and in 1934 was diagnosed as suffering from disseminated sclerosis. He died in Chobham, Surrey, on 11 August 1937. In the following year his widow was awarded a Civil List pension.
