Queens South Africa Medal

[Roy W]

I wouldn't automatically presume he was Canadian, he could well have moved to Canada later in life, or the medal been bought by a Canadian collector and shipped to Canada.
There is a book titled "No Colours, No Drums" re Canadians in the South African Constabulary by Jim Wallace it is still available online. Your man isn't recorded among the names of the Canadian Scouts of the time in other resources.

No Colours, No Drums: Canadians in the South African Constabulary

It was printed in 2008. It has all the Canadian names and lots of detail.

An identical 3 clasp SAC QSA accompanied by the recipient's WW1 pair sold at DNW this August for £220 hammer, so final price with fees around £286 for the three medals.

Lot 15, 20 August 2020 | Dix Noonan Webb

Hope that helps