I have not found anything new, but I can prove your kinship. Perhaps he had changed his name, and has to be researched phonetically, and haven't had time. Here is an excerpt from the Craven Co., NC Court records identifying Stephen's 8 children: "...That Stephen Wetherington late of Craven County died intestate in the year 1803, possessed of and entitled to a very valuable personal estate. That the said Stephen, left eight children viz your petitioner, Halley, Laney, Betsy & Mary Wetherington and John Wetherington, Nathan Wetherington, Ann the wife of Nathaniel Peters and Southey Wetherington, who were entitled to distribution of his personal estate of said intestate...."
My ancestor was Ann Wetherington & Nathaniel Peters. Your Southey was spelled a little differently in this record.