Thomas Coates of Laurens SC

I have been obsessing about finding the parents of Mary Margaret Coates,wife of Joel Cooper Blackwell. So far I can find circumstantial evidence in the 1830-1880 census placing Thomas and his wife Frances close to various kinfolk and at one time close to 2 households from Joel and Mary. Thomas Coates lived in the Simpson's Mill/ Ekom area or Waterloo District of Laurens County. November 18 1837, He and John Gary donated land to Union Baptist Church but cannot find his burial or other information.