If you are certain of his birth in Platte, MO then you probably have more info than the person you are attempting to reach? Only two public family trees and neither have been thoroughly researched. Findagrave memorial records John's death 1928. Online death certificates viewable/printable https://familysearch.org/
Jno W. Davidson (29 Dec 1854 - 2 Sep 1928) and Florence Rebecca Davidson (23 Jan 1865 - 16 Aug 1938). John Jr. witnessed his father's death certificate and did not know his paternal grandparents. I'm not related.