Unregistered Memorandum of Family Settlement and Relinquishment

My maternal grandfather died without a will. nnMy mother 's brother made her sign a Memorandum of Family Settlement where she has agreed that he brother will have sole right to my grandfather's house, including right to sell. The document is notarized but not registered. nnHe had made some verbal promises in return which he now refuses to honor. Also, he has used the document to get the title(patta)of the house in her name. My questionsn- Does my mother still have a share in the property as no settlement or relinquishment deed has been registered?n- Can she stop her brother from selling the house ?n- If he sells the house, can she claim her share from the proceeds ?nnThanks.