Dead sisters property division

My aunt died 2 years back in her house one of my uncle is living alone he has no children no wife he is well settled fellow have crores of properties.He and our other uncle are close so they have joined together and not giving my father his share in aunts house they both are getting benfit by my uncle staying there we are in problem. What to do?He is saying he gave money to my aunt to build house so we have to give him money.My father gave my aunt a portion of money to build the house but proof