Ownership in chawl

Can u help in knowing a ownership in chawl system. My friend dad and mom expired 6years ago leaving behind a room in a chawl. He is the youngest in the family as he is well settled therefore he has ask in elder brother to take care of the rooM. now of suddenly he comes to know that his brother has sold the room in the chawl without his consent and his sister concern. He has by ways made the electric bill and ration card in his name without made know to the other heirs