Property dispute between me and brother's wife family

Hi All, My father bought some agriculture land and registered to my name and some acres to my mother and also later he bought some more acres and he registered in my name (I have major contribution of money from my salary). I have a younger brother who is little not social and mentally that strong to make decisions and he just sits at home idle. He dont have any knowledge of how things works and he is not good in anything. Because of this reason my mother property also registered in my name. Now sometimes i feel my brother's wife family is making an issue and trying to brain wash my brother and ask for the property share. And we don't trust my brother's wife and his family. If we register it will be like they will be enjoying all his property share. First of all do they have any rights to ask the share as everything is in my name. I want to take care of my brother and i want to support his needs as long as possible and I want to transfer some property to his kids if it happened to be and once they grow up. But i want to control everything and I don't want my brother's wife family to disturb us.. please help me here. Thank you so much in Advance. Best Regards Ramu