Less than 10 minutes on the LAC site uncovered his name and most of his file. Previous service in South Africa he was president of a lumber company in Canada when he enlisted in 1915. He eventually rose to the rank of Lt-Col and was awarded two Mentions in Despatches and the DSO.
If you spend some time on his pay allotments you may even find his repayment for the Colt.
For more information on the purchase of the Colt 1911 and the Mills holster I recommend "Canadian Military Handguns - 1855 to 1985" Museum Restoration Service, by that incomparable Canadian arms historian Clive M. Law