What is the ruling on working with a manager who does not pray, listens to music, and watches pornographic channels? And is the sustenance earned from this work unlawful?

Your earnings and work are not connected to the condition of your manager, who abandons prayer and listens to and views forbidden things. You must continue to advise him without becoming too close, lest he influence you. Apply the rulings of Sharia (definition) concerning him, such as not initiating greetings with him and prohibiting heartfelt affection for him, because abandoning prayer is an act of disbelief and apostasy. If you work with non-Muslims, be careful not to befriend them, love them, or show loyalty to them, and adhere to the Sharia rulings related to them.