Firing an Employee Who Doesn't Pray
Question :
Should I endeavor to fire a Muslim employee who works in my department but doesn't pray?
Answer:
It is incumbent upon you to advise him first, and perhaps Allâh Almighty will guide him; if the advice has no effect, fire him, because by not praying he has become a disbeliever, an apostate.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 8 Page 87