This John Decker is the son of Lucas Decker (DOB: 27 Aug 1727 NY DOD: 1751 Hampshire Co WVA. Lucas was killed by Indians.)John's mother was Sarah Kuykendall (DOB: 1732). She married 1st: Lucas Decker 1749 Hampshire Co WVA. She married 2nd: Lawrence Hass @ 1760. This Lucas Decker was the BROTHER of Jan (John) Decker & brother-in-law to Jan's wife, Dina Kuykendall. (John Decker (b.1750) was Jan & Dina's NEPHEW.)
https://www.findagrave.com/memorial/61907812/john-decker