Maintenance and property share claims for mother and children

My parents got divorced long back its almost 16 yrs back. Actually the conflict happened long back during 1990's. My father is kind of money minded, he expected extra dowry from my mother's side. He used to raise a cwarel intentionally and he left my mother along with me and my sister in my maternal grand father's house. And my grand father(Retd govt employee) took the responsibility of taking care of my mother, my sister and myself and in meantime my mother applied for monthly maintenance as she thought, my father would change his mind and come back to us. But in contrast he applied for divorce and case went for some years and in meantime he produced some false witnesses stating that my mother is rude person and he won the case, as a result divorce was issued but my mother didn't approached the higher court due to some health issues with my grandparents. So my grand parents beared us nearly 18 years even they gave their own house as a gift deed to my mother and right now they were no more. After that incident my father came back(after 18 years) to provide us further education, I mean graduation and monthly maintenance was provided. Recently I came to know that he got remarried(At that time my sister is some 16 years old). So I have some few questions regarding the monthly maintenance for my mother, the property share my mother can claim etc.as he is harrassing my mother using some filty language which I cant explain to you and very soon he is going to get retired and he has wrong intention to stop giving money to my mother and asset share to us.(My father is a govt bank employee and he earns 12-13lakhs per annum).