Can Tripartite agreement be declared null and void

One of my friend is a builder who had entered into a development agreement with the owner development agreement was signed which was notarised but afterwards the the owner entered into Tripartite agreement with another builder and cidco , my friend has already paid Rs. 30,00,000 to the owner as per the development agreement . What Legal remedies are available to him. We want to that the Tripartite agreement be declared null and void , stay for creation of third party interest and futhercc to others.