He can't be documented because there is no evidence he ever existed.
The Eastern Cherokee applications in that group were all rejected since there was no evidence any of the applicants had any Cherokee ancestor. Miller said in his report that it appeared from the testimony that the family had an ancestor "of Indian extraction" from a Virginia tribe at some time before the Revolutionary War. The testimony said that Betty Pledge Poindexter, who lived in Louisa County, Virginia, and died in 1816, was the daughter of a woman named Betty Donahoo, who was the daughter of an Indian Chief.
The Cherokee never lived in Virginia or had anything to do with the Powhatan.
There is no historical/contemporary document which names a "Chief Donahoo" - the local Native Americans on the James River (Pamunkey, Rappahanock, Nansemond, etc.) and were wiped out by 1700 or reduced to tiny reservations. Miller noted that the family had been recorded as white and lived as white back into the 1700's.
Some members of this family had tried to get Cherokee citizenship in Indian Territory in the 1890's and were also rejected.