It may be possible to confirm family relationships by comparing test results with Joe or other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
Y-chromosome DNA test-takers in his direct paternal line on WikiTree:
Family Tree DNA Y-DNA Test 111 markers, haplogroup R-M269, FTDNA kit #MI11061, MitoYDNA ID T10900[compare]
Mitochondrial DNA test-takers in the direct maternal line:
Family Tree DNA mtDNA Test Full Sequence, haplogroup H, FTDNA kit #MI11062, MitoYDNA ID T10899[compare]
It is likely that these autosomal DNA test-takers will share some percentage of DNA with Joe:
AncestryDNA, GEDmatch A236201[compare], Ancestry member joe_farler