Step father

Hi My stepfather manipulating my mother and taking all kinds of authorities, he married her after his 1st wife's death 1 year back. 1. I wanna know that for that marriage IS IT TRUE.. they must take stepdaughter agreement r sign? 2. I had a step-sister what is her rights towards my mother's property? {born to my mom & stepfather.} 3. My mother had an affair with my stepfather before she married my father...after that my father came to know the truth and they got separated.! I even don't No about my biological father. 4. I came out of that house and did love marriage and living happily. now my sister called me and told that he was taking gold, property after property ....he was telling my mom to sell the lands, handling all her salary to him. this was happening from the past 5 months I don't No why? My mom, she doesn't believe any1 in money matters... I knew that we both daughters are her nominees for every asset she had, few months back she changed everything into his name and listening to him. 5. We both sisters decided to fight together but how? 6. My stepfather had 1st wifes children 3 male and 1 female all r settled. 7.is there any chance that he giving that money to them? 8. All want is we don't want him my mom and he should not meet and come to my home. Is there any law? that I can get court notice to him. 9. He claims that I'm her daughter after marrying my biological father she slept with him. 10. Stepfather had two types of identity, two names, two Aadhra cards, two voter cards, he changed his age too. Retired ASW ..THIS is what I know about him, I don't No too much Thanks & Regards