Protection offered by the law against abuse of minority

Sir 1.My father has 3 daughters and one son (myself). 2.My mother is a step mother who has one daughter (the last of the 3 daughters. ie., I have two sisters born to my own mother. 3.The said property was a self acquired property of my Grandfather who through a will bequeathed it to my father. 4.The women (my step mother, two own sisters and step sister are teaming up with my father's consent to sideline me and cheat me of my share. 5.The daughters have already been given their dues in the form of jewe?llery and deposits. 6.How can I defend myself if the will is written in favor of the daughters 6.With nothing given to me until now, I am being sidelined in a sale negotiation underway. My questions are: 1. Equal share to daughters is only after considering the entire NETWORTH. Can that which has alraedy been given in other forms be considered in arriving at the EQUAL SHARE. 2.Can my father and these women enforce sale without my consent . 3.How can I defend myself. 4.Has my father a right to sell? Regards R.Ramakrishnan 9655245120