The couple had three children, Michael (born 13 February 1950), Jane (30 September 1955 – 26 December 2004), and Charlotte (born 29 June 1959). Jane, along with her 15-year-old daughter, Lucy, and her mother-in-law, also named Jane, were killed in the Indian Ocean tsunami as it struck their villa on the coast of Thailand on 26 December 2004. Michael and Charlotte are both involved in the dramatic professions: he as a director, she as an actress. Sim's younger brother, Gerald, who died on 11 December 2014, was also an actor.