Remember the Sask. connection was way back in 1922 when Charles and Mary came to Canada.In 1928 when Mary and your Mom return from Ireland,they proceed to Vancouver which is their permanent residence.
Mentioning our census..the last Canadian census that our laws allowed published was way back in 1911/1916!!!
I've looked quite well and haven't found an obit for Douglas so assume he's still around.But does he want to be found by you and your Mom?? Have you folks seriously asked yourself why he's never tried to contact you?
I do wish you luck..maybe the Hamilton/Nepean/Ottawa phone numbers will lead you to him or to a relative.