The text says Sai Baba left his body. Does this mean he is gone and can no longer help his devotees?

No, the text strongly refutes the idea that he is gone. Chapter 43 clarifies that Baba's departure was a conscious act where he 'burned the body in the fire of Yoga' and 'merged himself into the unmanifest.' It is not an end but a transition to his 'previous unmanifest state.' The text assures that from this state, he 'always keeps the devotees awake' and remains firmly imprinted in their hearts. His protective influence continues, as he now fills the entire 'moving and non-moving world' as a powerful, ever-present force.