It may be possible to confirm family relationships with John by comparing test results with other carriers of his Y-chromosome or his mother's mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
Wilhoit-1388 and Wilhoit-622 appear to represent the same person because: HI, This appears to be the same person in our trees. Same parents and spouse. and approximately the same Birthday. day and month are the same. year is a little off. I think a merge is probably appropriate here. Thank you.