I can't access these Ancestry.com records, but they might be clues.
1916 Canada Census of Manitoba, Saskatchewan, and Alberta
Name: George Hook
Birth: 1886
Residence: township, city, Lethbridge, Alberta
Canadian Passenger Lists, 1865-1935
Immigration & Travel
Name: Matilda Hook
Birth: abt 1914 - Canada
Departure: Southampton, England
Arrival: 8 Dec 1929 - St John, New Brunswick
There were several George Henry Hook gents that were killed in WWI; members of British units. He may have gone back to UK
http://www.cwgc.org/debt_of_honour.asp