When you realize that it’s been decades, literally, since Ethel Kennedy has given an interview, this new documentary is a TV treasure by that measure alone. Add to it the fact that it’s a documentary by Ethel’s daughter Rory, with whom her mom was pregnant when Rory’s father, Robert F. Kennedy, was assassinated in 1968, and… wow. Ethel, 84, has a lot to say, and says a lot even when she opts to remain silent. And if her reactions and reflections don’t get you