You should first find out what the teacher's usual character and reputation are like, and what is the reason for borrowing money from everyone. Don't worry if he has something urgent at home, as long as you can help him. If he blatantly asks for money, corruption and the like, you should not hesitate to report him, otherwise he will hurt more people. You are doing good, you can't pity the wicked. You can ask him, "Teacher, are you at home?" Do you need money now "and so on, so that you can remind him that it is time to pay back the money. If he has something to do, you will be moved to ask him, which may achieve the goal of killing two birds with one stone.