My Father's elder brother harrasing us, not allowing to repair leaking roof of our house

Hello Sir, My parents living at ground floor and his elder brother is at 1st floor of same house, Since the construction of house in 1960's, My father living at same house with my grand parents and served them very well as a son till their demise. Father elder brother who got separated after his marriage was living in a government house but after he got retired in 2004 and my grand parents demise, he asked my father to construct 1st floor where only 2 rooms were build. So, my father allowed him to construct 1st floor for his elder brother accommodation but after few months, leakage was there at roof of our rooms on top of which his elder brother kept his bathroom. In 2012, we were getting little repairs at ground floor and father's elder brother kept a case in court to stop any kind of repairs. So now because of leakage our rooms condition getting worse for living. My father tried himself in so many ways to convince his elder brother and even through relatives but he is not listening to my father. What could be the solution to get ground floor repair ?