According to research by Charlie Millberry on the Alewine family sent to me by Steve Etheridge on April 1999, Sarah (b. 1806) is a daughter of David and his first wife Martha Anderson. David has a brother (b. October 20, 1805) and a son named Reuben. I have Sarah's brother, Reuben listed younger than her, but I do not have a birthdate for him.
I will be glad to exchange any information that I have. Anne