Ancestral Property

Hi, my mother’s family poses an ancestral property of 7.5 acres of agricultural land and a house in 16 cents area near to Vijayawada. The same has been divided with oral partition among my mother and her brothers 25years back. They are 7 siblings ( 6 brothers and 1 Sister) and their parents passed away at a early stage and the elder brother took the responsibility of the family at the age of 17-18 and for almost 15 years they were in joint family and my mother’s elder brother got the entire property transferred on his name without the notice of his siblings (when they ever young). in 1975 my mother got married and he agreed to give a share of 1.65 acres to my mother as Stri-Dhan. In 1994 the joint family got separated and the property was divided equally among all brother. However, there was no written partition. Later when asked for written partition the elder brother was giving health reasons and was avoiding for documentation. Each one of them are enjoying the returns on the agricultural land and there is no document evidence as such. Now the elder brother is died and his son is claiming ownership on the entire property and asking all brothers and sister to leave the house. In some point of time, this guy had taken the signatures on a white paper from all the siblings and now showing them that they don’t have any share in the joint property. All this while they were mentioning it to us that we have our share of property as discussed orally. All the documents are with them and in last two days we have learnt that my cousin sold half of the property long back. Please help me how to deal with this case. • Can we approach court in this case and file a legal suite • What all documentation I need to collect for filing a case • Any specific fee I need to pay • Any other points I need to note