Oct. 8 (UPI) -- Joan Kennedy, a prominent U.S. mental health and addiction advocate, has died, her family said. She was 89 years old. The first wife of the late Sen. Edward M. "Ted" Kennedy, D-Mass., Joan Bennett Kennedy died Wednesday in her sleep at her home in Boston . "Besides being a loving mother, talented musician, and instrumental partner to my father as he launched his successful political career, Mom was a powerful example to millions of people with mental health conditions," her son,