Complex sentence: His ability had come naturally since his father, a coal-mine foreman, was a former musician who played drums in the local band in his spare time with his mother, before her marriage, had been a pianist in a vaudeville act.
Split into simpler sentences: His ability had come naturally since his father, a coal-mine foreman, was a former musician who played drums in the local band in his spare time. His mother, before her marriage, had been a pianist in a vaudeville act.