Parents seperated how to claim share in father's property

My father died before 2 days.I belong to hindu,Coimbatore,pillai caste.my father and mother got separated before 30 years.I stayed with my father,my mother and sister lived seperately,but they aren't divorced.my father didn't write any document,so how do they divide the property..into three shares?already my father had given my mother 14 cents of land and with that they have done marriage for my sister... Now if my sister and mother say we don't want the house.what is the procedure to document it?and also I want to know,if they say after sometime we want a share should I have to give them