Regd Property Legal Rights

Hi Sir Please guide me, My Father has Properties(All Self Made) worth 1CRL,80L,& 40L. , We are 3 Children's(Me from Deceased First Wife) My Younger brother & a Sister from 2nd Wife. Currently I am working in a Private Firm from past 13 Years and have been away from Step family,My Father is now thinking of dividing the properties, among children, But he is not dividing in proper way, he is thinking of giving the 1Cr property to Small Brother as he is looking after it, 80 L Property to my sister, which is run by father managers and 40L property to me. I am requesting my father to give share 30% in 1Cr Property. Although he is willing to give , my step mom and my brother are interfering in his decision.not to give the share. Also please note that, my father had left my mother penniless and he did not legally divorced my mother at that time and she died of illness, but my father took take care of me as per request from my grandfather(My Mothers Father). Also my step mom is not legally married as my mother was still alive and they were married in an temple.Please advise what are my legal rights and my decesed mother.Can i claim share of my Mothers too. Please Advise How Properties can legally divided without any problems.