Brother got his share without my approval

we have a house and some vacant land associated with that. This was bought on my mothers name. I have one elder sister (died 20 yrs before who has one son and daughter) and a brother. I am married , My brother without our knowledge got his share ( all service area land) from my mother who is not educated. In that land only, drinking water well, toilet/ washrooms are available. My father died recently and mother is living in that house with my financial support. My brother was not taking care of my father and now not taking care of my mother. Now my brother is trying to sell that land , if it is done, my mother can not live in that house without water/ toilet. Kindly advice me how to stop my brother from selling that land.