Complex sentence: Viewers could see Céline Dion leaving her home with her husband and their son who attended his mother's show, Dion in her dressing room or in the elevator that took her to the stage.
Split into simpler sentences: Viewers could see Céline Dion leaving her home with her husband and their son who attended his mother's show. We saw Dion in her dressing room, in the elevator that took her to the stage.