The 1940 US Census shows two possibilities. The first Patrick was born circa 1903 in Missouri, USA and in 1940 was renting a home in Compton, Los Angeles, California. His occupation is listed as Book Keeper Clerk in government business. His wife, Mary, was born in Ireland circa 1900.
The second Patrick was born in Ireland, circa 1907. In 1940 he was a US naturalised citizen and living in Boston, Suffolk, Massachusetts with Mary, born 1912 in Ireland, also now a US citizen, and two children both born in Massachusetts - James (or Janes) M. circa 1938 and Mary P. circa 1939.
Another possibility comes from "Hazel's Family Tree" on ancestry.com managed by "19Free2Fly". Patrick Francis Fahey, 1905 - 13 May 1955, married Mary Cecilia Richards Paull in 1927 in Australia, three children - Kevin, Noreen Muriel and Michael Desmond.
Hope that helps. Mary