Selling property

We have a flat in Bangalore. The property is in the name of my father, our family consist of father, mother, 1 son & a Daughter (my self). My father and mother are living apart from past 10 years (not divorced), my brother is living with my father and I am living with my mother. currently me and my mother are living in this flat. my father and brother are living separately. The flat was bought in 2004 by a down payment of 1 lakh rupees by my father, my mother has payed entire installments since then and completed all installments throughout her lifetime which sums up to more than 40 lakhs. now when the installments finished, my brother and father wants to sell the property (initiated by my brother). where as me and my mother who lived in the flat for years togather and payed all its instalment are not willing to sell the property. I need guidance if My father and brother goes for litigation how strong are we to defend the case so as to not to sell the property? require kind support