Uncle trying to capture the property

We have a property which was in the name of my mother. She died when we were too young. And the property legally transferred in the name of me, my brother and father. Our family broken after mom gone. Me and my brother went to hostel. Father paralyzed in his 50s. We had no good relation with father too. During my marriage, uncle took the advantage of the situation and offered to build house for marriage purpose. The land is in a very posh area of the city. Uncle took 25lakhs 7 years back to build the ground floor. In around 3000 sqft land he build only one 2bhk and driver room and rest parking. Till that date I was not talking to father frequently neither I had any connection so I didn't know what's happening. After building the ground floor the uncle build 2nd floor from his money. He build two 3bhk on 2nd floor. I thought father allowed him to build so i never asked. As my father lives in village and because of health he didn't come to see the home. I am working in other state and don't visit frequently. So the uncle rent the ground floor and took all the rent himself. He said he invested 13 lakhs in ground floor so he will take money. Father was helpless that time. During covid when my brother came back to home state he asked to vacant the property. Uncle denied. He said till you transfer the 2nd floor to my daughter we are not going to leave the ground floor. When my wife asked he too denied. And when I talked to them they said either give us the money we invested or the property. We are ready to give money and take the 2nd floor. But now they are not ready to get the construction cost. He is saying he invested 50lakhs 5 years back so he gonna sell the 2nd floor with current price only. Note- - My marriage was held in that house. My father or brother never live in that house. I hardly lived 1month in last 5 years. - Uncle have not given any lease amount for the land nor rent. We didn't get a single rupee in 5 years after construction. - Uncle had a vigilance case in 2016. The vigilance officer came to that house too. Aunty told them the owner are living in other states. We are living here as tenant. They did not mention about the 1st floor property. My question- - Should we give more money than the construction as he is demanding? - If yes then can we charge lease amount and rent amount on them and deduct it from final price? - can we consider the depreciation as well? - We are ready to give the construction price but they have enjoyed the whole property for last 5-6 years. - I want to go what is legal to do. If they legally deserve more money then we are ready but we don't want them to cheat us again.