Preventing family members from selling ancestral land

Hello Sir/Madam, I am looking for legal options that are available to prevent sell of ancestral agricultural land by my elder brother. To receive best consultation I would like to provide additional details below: issue:- we are three brothers, my mother is still alive but my father expired. i had bought some land 28 years ago on my mothers name but after that i moved from village to the city i didn't paid attention on things going around my house. now my elder brother is trying to sell that land and my mother is refusing to object on it. however she is saying she won't sign anything but i heard from someone that if my elder brother goes forward with the deal and he signs it and if my mother doesn't object the deal then it will be as per the law. i wan't to stop him from doing that. what are the legal options i have. i am from Bihar. Could you please advice me how I can resolve this issue legally? If yes then can you please provide brief description on legal options that I can avail to stop my elder brother from selling the land.