Who is Stosh Cosnowski from Wanda Hickey's Night of Golden Memories and what is their importance?

Stosh Cosnowski, Appears in The Star-crossed Romance of Josephine Cosnowski - Brother to Josephine Cosnowski who takes it on himself to warn the narrator that he had better give his sister a good time at the party. Stosh is a huge boy, smelling of a locker room where he spends a good deal of time. He leaves a dent the size of an elephant's footprint on the fender of the Olds just by putting his foot up there. He chases the narrator for blocks through the dark when the narrator makes a run for it from the party at the church. As a huge football player, he moves pretty quickly, but finally gives up and leaves the narrator to finish running home in the dark alone.