I'm almost sure this Charles Stigall is the son of Andrew Stigall born about 1856. If this is the one, then he was born about 1894 and died 1957.
Other than the same census information that you probably know of, I found very little on Amelia Mercer nor the Steely family.
In the 1920 Pulaski County census, Sloans Valley District, I noticed several Stigalls living in reasonably close proximity to Charles Stigall and his family. One was Orna Cox Stigall (family 99), who was the wife of Andrew Stigall and the mother of the Charles Stigall that I referenced. Charles' brother Dewey was living with her. Another was John T. Stigall (family 83), who was the brother of Charles. Another was Charles' brother George A. Stigall (family 100).Other close family members were near by too, such as Fountain Fox Stigall born 1839, John W. Stigall born 1891. For some reason, however, Charles and his family were living with John Dobbs and his family (family 125). They were living in the part of Sloans Valley that several Steam Rail Road workers were living. Charles was working for the Rail Road too. Let me know what you find. Hope this helps. Bernard A. Aleem Stigall Researcher