There's enough similar in your family description that I want to share with you what I know about my great grandfather, Edward Daoust. I understaood that he was French speaking and was deaf towards the end of his life. I am 52 and only have vague memories of him. I wonder if he is the same 'Edward Daoust' you mention here. He would have been born around the same time and place and from what I understand, had six children, one of which was my great aunt, Muriel Daoust, who was born sometime after 1915 in Idaho. Muriel married John N. Manning. Sorry, I don't have dates close at hand since I'm using some materiel that a cousin, Jeannette Manning, put together and what I have does not have dates.
I am Edward Joseph Archibald Jr., son of Edward Joseph Archibald Sr, and Rose Ida Secolo and my father was the son of Hector Archibald and Blanche Daoust, sister of Muriel Daoust.
I am an American but am currently living in France and would like to track down some of my ancestors here if at all possible.
So if any of this sounds familiar or promising, let me know and I can get more details from my cousin etc.