WWII Family Link

All the Pahlka family in the U.S. comes from a Charles and Elizibeth Pahlka and their eight sons. During WWII, a David Pahlka from Portland, Oregon was shot down in the Pacific. All ships were called out to search for the possible survivors. H.I. Pahlka, from Oklahoma was given a Navy cap with the name Pahlka written in it. It wasn't his but the downed pilot who still hadn't been found. Years later when in S.F. at a small reunion, H.I. tells his cousin, my aunt, Lucille, that story and she said her husband, 'Dutch' Most, had rescued David Pahlka from the water. H.I lived in Oklahoma, David in Oregon, and their cousin's husband in S.F. What are the odds of that link? How would one set up a mathematical proof? I think because my parents liked the other David, an war hero, I was named after him.