“I hate to say it,” the rhythm and blues singer D’Angelo ventures toward the end of Questlove’s new documentary “Sly Lives!” (streaming on Hulu), “but these White rock-and-rollers ...

The film focuses on Sly Stone, a funk musician who headed up Sly & the Family Stone in the 1960s and 1970s ... relatable, everyday person. To me, that’s the dream.” What people don’t know is that Sly ...