Mother passed away intestate who will get share in property

Dear Advisors My Father passed away in 1999 leaving a will in favor of my mother. She passed away interstate in 2014. Subsequently the four legal heir's 2 son's and 2 daughter's off them me along with my brother and one sister executed registered release deed in favor of me in 2 properties and in one property in favor of my brother. Now subsequently the other sister filed an civil suit asking for 50% in the said properties. Her argument's r based on some Andhra judgement wherein she is claiming that release has to be in favor of the remaining. In the mean time my brother has agreed to give her 50% rights in the property wherein he had 3/4 share. My question is 1) What r might rights in the 2 properties. 2) Has their been any precedence wherein the court has over ruled the release deed.