Mutual agreement between family member for compensation appointment & father provident funds

My father in law died before 3 year retirement of his state govt. services in U.P. revenue deptt. being a lekhpal (patwari) .his family has 4 sons and 1 daughter . all sons and daughter were marriage . out of 4 sons 1 younger son is died 1 year ago. after death of his son , wife of son and his 3 little child's lefts in his family . my late father in law family member i.e. reaming 3 sons and sister in law (wife of late younger son of my late father in law) executed a mutual agreement in 1000 rupees non judicial stam papper ,that contains a mutual statement that we 3 sons is agree to give full provident funds etc. to my late younger brother wife after that late younger brother wife is agree to give acceptance of compensation appointment of his brother in law (dewar) .now the brother in law is joined in compensation appointment in govt deptt. but now they all 3 sons is refused to give provident fund etc. to his widow sister in law . in this situation what she will do?..she approach to higher authority such as DM/SDM, but no result came out.she has only one written document ,one 1000 rupees non judicialy stamp mutual aggrement singed by all 3 sons and window sister in law also withess singed of her family member like uncle ,anty etc.plz provide nessesary advise .