It may be possible to confirm family relationships by comparing test results with Larry 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 37 markers, haplogroup I-M253, FTDNA kit #34276
It is likely that these autosomal DNA test-takers will share some percentage of DNA with Larry:
AncestryDNA, GEDmatch A272065[compare], Ancestry member lm_peter