How to sell an ancestral property without permission of father ?

Dear Sir/Madam, Our family has two property, a flat and a piece of land. My father bought land in the name of my mother and the flat he bought from sell of our paternal property in the name of my younger brother. After demise of my mother he said that , you will take the land. Now want to sell that land to buy a flat but they (father and brother) are saying that we will not give this land to you. The paper of land is with me. How can sale this property without them? What should I do now ? Please help with proper solution.