There is a death record on familysearch.org for J. Marvel Brewer, which is an error in transcription for J. Manuel Brewer. John Emanuel Brewer was the son of William Riley Brewer. This death record lists the surname of Manuel's mother as "Hix".
There is a 17 year old Dianah Hicks, daughter of Samuel Hicks and his wife Nancy Ward, listed in the 1850 Watauga County, NC Census. She could possibly be the wife of William Riley Brewer.