Is the money remaining from tuition fees, which the husband receives when helping the financial officer during holidays, rightfully his? And if not, what should he do with it?

The small amounts of money that their owners leave with the employee fall into three categories:

1. If their owners left them by mistake or due to a lack of change: they remain the property of their owner, and they take the ruling of a lost item (Luqata) if their owner is not known. 2. If their owners explicitly state to the employee that the money is for him: this falls under the category of gifts to employees, and the relevant fatwas can be consulted. 3. If their owners left them willingly and by their own choice, without transferring ownership to the employee: this money belongs to the employee's workplace, unless there is an explicit textual or customary permission from the workplace allowing the employee to keep any amount exceeding what is due.

It is better for the employee to inquire with his workplace to avoid doubt and to be cautious in matters of religion.