Complex sentence: After the war he returned to bookkeeping for a bond office before spending some time and opening a Hudson-Essex dealership in McKeesport with the $5000 his father had invested for him during his time at the supply company.
Split into simpler sentences: After the war he returned to bookkeeping for a bond office for a while. He then opened a Hudson-Essex dealership in McKeesport with the $5000 his father had invested for him during his time at the supply company.