Elton John, Brandi Carlile on their dream collaboration

Years ago, Elton John was a flicker of hope in a confusing world to young Brandi Carlile, a girl coming of age and struggling with her own sexuality. Today, the two music superstars are not only friends, but also collaborators, recording an album together, “Who Believes In Angels?” They talked with correspondent Tracy Smith about pushing each other artistically, and the 78-year-old John’s emotional response to the album’s closing track, “When This Old World Is Done With Me.”