Complex sentence: He left that job to spend more time with his family, but eventually returned to baseball as head varsity coach for Regis Jesuit High School in Aurora, Colorado, where in his first season in that capacity he led the team to the 5A semifinals.
Split into simpler sentences: He left that job to spend more time with his family. Weiss was the head varsity coach for Regis Jesuit High School in Aurora, Colorado, where in his first season as head coach he led the team to the 5A semifinals.