Grand father named property belongs to his sons equally right?

Need a help regarding property quarrels: Family Background: My Grandfather had 4 sons and 7 daughters. As of now 3 sons and 3 daughters are alive and all daughter are married before 25 years and given the good amount in the bank for grandchildren. One of the Son (bade papa) dead in 2004 due illness before to that his son and wife are also passed away but had three daughters(all are married). Property: We have a house in 600 square yards with two stair building on the name of Grandfather which is occupied (or grandfather was given) one block each son and one room for each son from remaining block. For on the son having a separate build that area. Question: My father younger brother (next to my dad) is saying that whole property belongs to him. Because he is saying that in 1994 grandpa wrote a will that this property belongs to grandma and grandma wrote a will to him in 2000 but all are bull shit and not valid. They have some signature of grandma and grandpa on white paper. Reason:My father (second son to my grandfather) and elder brother are signed on papers in 1979 to grandfather that they are divided from him. This was signed to show to the income tax for some reasons but they didn't mention that this property belongs to my father younger brother. Points for reference: 1. My father and his elder brother signed the document in 1979 (For how many years these papers are valid) but grandpa constructed and moved to that living property in the year of 1983. 2. We had a doc, which was written by my grandfather on a white paper by saying which block belongs to whom and all the four sons signed on that document. 3. They are saying that grandpa wrote a will in 1994 and dead on 1996 but at that time (in 1994) or after dead they pushed us out from and never said (or shown) anything to us till now. Even my grandma didn't say to leave that home either in 2000 nor my father brother said anything after her death (2002). 4. Since 1983 we are all residing in the same house which means from the past 33 years we are living there.