In some specific situations, is the son married and living with his mother? If so, the mother has the right to discuss and collect rent, which is completely normal. The second situation is that the son is not married and lives with his mother. This is an internal matter between them and the agreement is to contribute to the living expenses, electricity, internet, water, etc. for the mother instead of having to pay separately. As long as they find a suitable solution, all parents love their children very much.