Settlement deed

My mother did a family settlement deed of property between my brother and me in 2007 which is UNREGISTERED nd UNSTAMPED . This deed includes 5 witnesses one is senior govt employee Nd other two are advocates Nd rest family members . In 1981 this property's lease holder did GPA on the name of my father but my father did agreement to sale deed on the name of my mother in same year. In 2008 my mother made conveyance deed on her name. In settlement deed my mother gave me ground floor of the property and upper two floors with roof right gave to my brother. In 2010 mother made registered gift deed on the name of my Bhabhi without telling anyone in the family And through this registered gift deed same upper floors mother gave to my brother's wife. Now in August 2016 mother made a registered will on the name of my brother's son and gave my ground floor to him. And in September 2016 my mother expired Now my brother sent me a notice to vacant the ground floor. We came to know about gift deed and will after death of my mother . Can I challenge or apply for cancellation of gift deed and will on the basis of my UNREGISTERED settlement deed ? And my UNREGISTERED settlement deed is valid till date?