Property dispute after father's death

Hi,my name is shweta.we r two sisters and a brother.my father died on 31st December 2017.after that my brother start troubling my mother for property.we have one property in my grandmother's name and three properties in my mother's name and one property in my father's name and that was in 50% partnership with someone.He has a Scorpio car and two bank accounts, he neither made any will nor nominate anybody in all these assets. Last month he filed a case on behalf of my grandmother for demanding the maintenance from my mother.My mother doesn't had any source of income despite of the rent coming from father's property. Maintenace tribunal ordered her to leave the house she is living in becoz it is in my grandmother's name.Now we want to file a case for my father's car for my and my sister's share.Can we do that? What will be the chances of winning the case and what would be the approximate cost of all this procedure including lawyers fees and other expenses.