Complex sentence: La Rocca led this band on tours of England and the United States into the early 1920s, when he suffered a nervous breakdown, and returned to New Orleans and retired from music, going into the construction and contracting business.
Split into simpler sentences: La Rocca led this band on tours of England and the United States into the early 1920s, when he suffered a nervous breakdown. He returned to New Orleans and retired from music, going into the construction and contracting business.