It's occurred to me that even aside from making sure he's not speaking Google Translate European French, modern Quebec French might sound anachronistic in that era. I've looked around on Google and various library catalogs, and I've found tons of material on American English slang of the 1920s and '30s, and a few pages about modern Quebec French idioms. The best resource I've found about historical Quebec French, though, is about two paragraphs in the Wikipedia page on Quebec French in general.
I'm beginning to wonder, are there even any sort of materials of the type I'm looking for? For that matter, is there anything on Canadian English in the '30s?