Today, Sly Stone — one of the greatest figures in soul-music history — is homeless, his fortune stolen by a lethal combination of excess, substance abuse and financial mismanagement. He lays his head inside a white camper van ironically stamped with the words “Pleasure Way” on the side. The van is parked on a residential street in Crenshaw, the rough Los Angeles neighborhood where “Boyz n the Hood” was set. A retired couple makes sure he eats once a day, and Stone showers at their house. The couple’s son serves as his assistant and driver.