Complex sentence: His father, Jacob Grosberg, immigrated to the United States through Germany to avoid being drafted into the Russian Army and in doing so, changed his surname from Gans to the more-German-sounding Grosberg.
Split into simpler sentences: His father, Jacob Grosberg, immigrated to the United States through Germany to avoid being drafted into the Russian Army. Jacob changed his surname from Gans to the more-German-sounding Grosberg.