Mississippi and Alabama Dept. of Vital Records do not have death records back that far. Try the clerk of court in the county of death, but they may not have them either. I don't think you will find wills. You could contact the historical society, public library, or museum in the county for possibly other help.
If you can find birth, death, or marriage certificates or records for any of Palathia's children, you may find information about their father.
I haven't been able to find Robert Nelson Doughty or Jeremiah C. Doughty in a cemetery.Many of my line are buried in Concord Cemetery in Fayette County. In the Big Creek Cemetery in Tuscaloosa County are buried Jeremiah Sr., his mother Nancy,and Martha E. Beall Doughty, the wife of Jeremiah C. Other family members may also be buried in these cemeteries.