Since you seem to know a bit about some of the siblings, maybe you know where they died. If you do, try finding their death certificates. Almost all death certificates list the persons parents' names. You say that two of the women's married, and one married Sylvester. For each one that was married, if you know thriller state and married name, you may find the parents' names. Remember that women may have been listed as Kathryn Marie West, Kathryn Pringle West, Mrs. john A. Pringle, K. M. Pringle, etc. est wishes!
Dolores Miller Pringle