Your earnings and your work have nothing to do with your boss’s situation or his not praying or his listening to music or watching haraam things. You should keep on trying to advise him without getting too close to him, because there is the fear that he may influence you.
You also have to apply the rulings of sharee’ah with regard to your boss, if he continues to neglect prayer – such as not initiating the greeting of salaam with him and not liking him in your heart. We have already discussed a great deal about the rulings on not praying and the fact that it is kufr (disbelief) and riddah (apostasy).
Shaykh Muhammad al-Saalih ibn ‘Uthaymeen said:
We advise this brother who works with kaafirs to look for a job where there are no enemies of Allaah and His Messenger, who follow religions other than Islam. If that is possible, what is how it should be. If that is not possible, then there is no sin on him because he is doing his job and they are doing theirs, but that is subject to the condition that there should be no feelings of love or friendship towards them in his heart, and that he should adhere to the teachings of sharee’ah with regard to greeting them and returning their greetings, and so on. Also he should not attend their funerals or their festivals, or congratulate them on the occasion of their festivals. (Majmoo’ Fataawa al-Shaykh Ibn ‘Uthaymeen, 3/39, 40).
And Allaah knows best.