Hi,

Oklahoma doesn't publish it's vital record dates. That's why you can't find their deaths.I checked Ancestry and FamilySearch and neither death date appear.

You can do a Google search for Jefferson County, Oklahoma Cemeteries and look for them in the inventoried cemeteries.

You can contact the Paul's Valley Historical Society, http://paulsvalley.com/historical-society/ and ask if they have death dates, obituaries and burial info. Successful Searching!