Linda, I have recently discovered (from a distant cousin in Calif) that Jacob Keever was definitely the son of John Keever of Jefferson Co., Ohio. William Keever and Elizabeth Keever were definitely Jacob's full siblings (they had the same mother; sorry, I haven't figured out who she was, yet). Elizabeth and William moved to Morgan County, Ohio. She lived with him until she entered the Morgan Infirmary shortly before she died.
Jacob's half-siblings included my great-great-grandfather Joseph, born 1817 (the year your Jacob was married).
Because I don't have their birth order, I'm not sure who are half- or full-siblings of the following, but they are listed in John Keever's will (Morgan County Will Book 0, Page 322)as his daughters:
Catherine Keever Carson, Elizabeth Keever (referred to above), Mary Keever King, Susana Keever Watson, Sarah Keever Tucker, MarthaKeever Jones.
What year was Jacob Keever born? And where in PA was he born? Do you know? Might give us a clue to who Jacob's, William's and Elizabeth's mother was. Thanks, Deb