Does the nurse's end-of-service bonus count as a debt upon the deceased that must be paid before distributing the inheritance, especially since it is mentioned in the contract, even though some believe it is not obligatory to pay it?

If the contract between your mother and the nurse stipulates a one-month salary as an end-of-service bonus for each year, then this bonus must be paid from the mother's estate before its distribution, because fulfilling valid conditions in contracts is obligatory.