All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
It is permissible to continue your job. However, you have to advise your Muslims colleague, but it is not your responsibility if he does not accept your advice as long as you did your best to get him to stop doing what displeases Allaah The Almighty. Please review fatwa 81589 in which you may find convincing evidence for your colleague.
Allaah Knows best.