Release deed

There exists an unregistered agreement, dated September 1962, pertaining to an immovable property (structure) owned by a Mother (Expired in 2012) survived by her four children. Three children executed and registered a release deed in favour of the 4th in 2017. Now, this 4th person intends to approach the court u/s.34 to 38 of the SRA, 1963 for a declaratory decree and to obtain an injunction against Municipal Corporation which has issued demolition order, after following due process, against the structure. (It is not known whether the Mother has made a WILL bequeathing the property to her four children, and the WILL has been probated.) Can this approach assist in saving the structure from demolition?