What should a Muslim worker do if asked to serve coffee and tea to those who are breaking their fast during the day in Ramadan, and is he permitted to do so under the threat of termination of his services and deportation?

It is not permissible to break the fast during the day in Ramadan except for a legitimate excuse. Whoever deliberately breaks the fast without an excuse has committed a major sin. It is not permissible for anyone to offer food or drink to someone they know will consume it during the day in Ramadan without an excuse, because that falls under aiding in sin, whether offered to a Muslim or a disbeliever. Disbelievers are addressed by the branches of Islamic law. The employee must not obey their managers in disobeying the Creator by offering them coffee and tea during the day in Ramadan as long as they are not excused, for "there is no obedience to a creature in disobedience to the Creator."