Hi, Have you obtained or researched Registrations of Marriage and deaths
You know John THOMAS - was born 1837 - Quebec - cd 1904.
married Isabella Jane ROONEY born 1841 Ireland dcd 1925
Registration of Death - depending on requirements of the time - and knowledge of the informant [ May mention names of parents - including maiden name of the mother.
Search Family Search Org Online
also DROUIN Collection
http://search.ancestry.ca/search/db.aspx?dbid=1091