"The Boys: The Sherman Brothers Story" is a terrific documentary produced by the sons of the famous composing team of Robert and Richard Sherman ("Mary Poppins," "The Jungle Book," "Chitty Chitty Bang Bang") about their fathers and their complex relationship.Robert, for example, the older brother and "poet," who wrote so beautifully of sweetness and optimism, was in the very first group of GIs to liberate the Dachau concentration camp, which had a profound impact on him and his relationships, especially with his brother.