My theory (and belief) is that Elisabeth "Betsy" WELLS was the elder "half-sister" of John Close. That said, here is the circumstancial evidence supporting that theory:
1) William FARROW named his grand daughter, Joanna FARROW in his will. William FARROW also named his children in his will, among whom was a daughter, Ann "Nancy" FARROW, who married Samuel WELLS.
2) Samuel WELLS and Joanna FARROW were called to court in 1778 in Yohogania County, Virginia (now defunct) for abusing Ann, wife of Samuel WELLS.
3) Records of Joanna FARROW can be found where ever (same places) and whenever (same times) records for Samuel WELLS can be found.
4) Joanna FARROW filed a lawsuit in Jefferson County, Ky against the estate of Samuel WELLS.
5) The letters from Elisabeth "Betsy" WELLS commenting on the bond between brother and sister, as well as Elisabeth admonishing John Close when she felt he needed admonishing (typical older sister ). That she addressed herself to the children of John CLOSE as their "Aunt Betcey".
After the death of Samuel WELLS, Joanna FARROW and Jacob CLOSE became the parents of John CLOSE.
6) That John CLOSE supported Elisabeth WELLS (sent her money and comodities).
7) That the letters from Elisabeth WELLS to John CLOSE spanned 40 years.
8) That Elisabeth "Betsy" WELLS was invited to live with the family of John CLOSE, and probably would have done so had it not been for her fear that he would die and leave her alone in "that other country" [Louisiana], or that a steamboat might explode with her on it.
9) That John CLOSE named a daughter "EliSabeth" [not EliZabeth]
By the way, DNA tests show that John Close's descendants' DNA is an exact match [26 marker exact match] with another CLOSE family in the same area, so we know John CLOSE was not the son of Samuel WELLS.
Elisabeth "Betsy" WELLS, a nun, was celebate, therefore, left no descendants.