بسم الله الرحمن الرحيم
(Fatwa: 1255/H-304/TH=10/1434)
Obviously the unlawful usurpation is haram. It is wajib on him to leave the unlawful usurpation. And he should apologize to his mother for the pain which he caused to his mother. What does the mother want to do? If she wants to take any suitable step for getting rid of unlawful usurpation then she is allowed as per the Shariah.
Allah knows Best!
Darul Ifta,
Darul Uloom Deoband
