Son's inheritance of fathers house

We are christians(middle-class) family in karnataka.My father separated(not divorced) from us 8 years ago. My mother & myself(only son aged-43years) are currently residing in one part of the house we have been living for the past 36 years as one family. The local court has granted an injunction against sale of the property(-mother has filed a case of no wife maintanence against my father-), and given full rights to my mother to stay in the house-he had kicked her out earlier-, so i am staying on this behalf along with her. Our lawyer says that, in case mother dies before fathers death, the son has to vacate the house and cannot lay claim(or inherit) to any part of the house. Is it true? Our lawyer says, i can be in the house along with my mother as long as she is alive. I actually don't have any shelter other than this. Can i lay claim to my share of the house(property), now OR after my mothers death. The entire house is under the ownership of my father, and the case has been going on since april 2008. In between he has sold 2/3rd of the house illegally-since there was a court injunction on it from day one-. I have an elder sister married living in harihar. So what can be done.