What is the ruling on a Muslim writing a Coptic result at the request of the Coptic company manager?

A Muslim must be proud of his religion and preserve its distinctiveness, and not switch from the Hijri calendar to other calendars, because the Companions adopted it and abandoned others. It is not permissible to participate with disbelievers in matters that concern them or symbolize their religion. The Coptic result should not be written unless its omission would lead to an unbearable harm. The Lawgiver has linked legal rulings to lunar months, which necessitates Muslims' reliance on the Hijri calendar.