Is signing for a colleague who is absent from work due to the death of a relative, with the manager's knowledge and leniency, considered a sin requiring expiation by paying a sum of money to the poor?

Signing the attendance register on behalf of an absent colleague is considered lying and deception. The correct procedure is to record their absence. Employees must adhere to work regulations and contract terms without lying or falsification. Whoever has done this must repent to Allah and resolve not to repeat such an act. They are not required to give away a day's wage from their salary as expiation for it. An employee is a private hire who must be present during official working hours, whether there is work to do or not. The absence of work is not an excuse for being absent. If an authorized official permits departure, there is no objection. However, if the manager tells the employee, "Sign in and then leave," this involves deception. The proper action would be to write "Departed with permission" or similar, to avoid the characteristic of deception and falsification.