According to wikipedia he moved to Canada in 1971 at age 21. It calls him Japanese-Canadian. I'd wager he's become a Canadian citizen by now, though I can't be bothered to research it. Do you have evidence that is he not Canadian?
If I move to the UK and invent something, is it automatically a British invention, or an American invention?
This is a pretty silly argument but the spirit (and purpose) of the invention is also clearly to make something more suitable for Canadian tastes of the time.
Well, certainly not European.
But, maybe - wouldn't it depend on where you filed your copyright/ patent/ trademark and possibly who you work for?
You're conflating a geographical area with a political arrangement. Not all Europeans are in the EU.
52 years? No, at best landed immigrant status. With the legendary speed of Canadian bureaucracy I expect he'll be made a citizen posthumously.