I've been researching my ancestor James Williams. I have multiples sources indicating he was born in Nash County in 1817. I found two heads of household in the 1820 census that fit that bill. Weeks and Granberry Williams which match two of the siblings of Bryant Williams you are searching for. They lived in Eatmon Township along with two other Williams heads of household, John and Drewry.
You mention that Drewry and Elizabeth are parents to several of Weeks and Granberry. Is this a guess or do you have something that leads you to this conclusion?