Source: Via Allan Miller from Facebook photo of his headstone.
Family Search: Allen Hugh Cathcart was born on 5 March 1896, in Fergus, Wellington, Ontario, Canada as the son of Wesley John Cathcart and Susan Hoyce. He lived in Chatham, Chatham-Kent, Ontario, Canada in 1930. He registered for military service in 1916. In 1916, at the age of 20, his occupation is listed as clerk. He died on 27 May 1969, in London, Ontario, Canada, at the age of 73, and was buried in Woodland Cemetery, London, Ontario, Canada.
War Diary of the 18th Battalion CEF 