Joint ownership of house.

My father built house in 1997 with loan taken by him Nd he died in car accident in 2002 without any will thus house was registered on name of my mother and us three brothers equally. Till now my mom is paying loan of said house and we all are residing in house. 1 year before eldest son my big brother got in ugly fight with Mom because of girl Nd misbehaved with my mother and left house 7 months before now he is married with tat girl Nd in influence of girls family.now my wanted to take loan for renovation of because she is working in bank also at place of my father but my brother is now allowing her to take loan because it also need his signature.my brother is also government servant nf independent while we two brothers are still dependent of mother as we are unemployed Nd still studying. Now I want to ask can my mother take 25% property back which my brother holds. Nd can she disown him from property because she going through lot mental torture. She has seen lot bad time in raising us now me and my small brother also feels bad to see her in such emotional candition after all sacrifices she made in her young age to give us good life