It may be possible to confirm family relationships by comparing test results with Roy 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 67 markers, haplogroup R-M269, FTDNA kit #430354
Mitochondrial DNA test-takers in the direct maternal line:
Family Tree DNA mtDNA Test, haplogroup H1-T16189C, FTDNA kit #430354