Who is Ahronchik from Tevye the Dairyman and the Railroad Stories and what is their importance?

Ahronchik is the young man who wishes to marry Tevye's youngest daughter, Shprintze. He lives with his widowed mother, does not have a job, and has no money of his own. Unfortunately, Ahronchik's mother disapproves of the match and the engagement is broken. As a result, Shprintze takes her own life.