Co ownership rights of a house with NRI brother

Hello all, I live in a house which was in my grandfather's name and he wrote in his will that both the sons are entitled to 50% right which means they are Co owners of this house. This land was bought by my grandfather and the house was made with everybody's contribution. My uncle is an NRI,he is a British citizen for the past 50 years. However he says that my father had not contributed anything towards dis thus he does not have any ownership. My father paid all the expenses fr maintaining this house fr da past 40 years and this amount is much more than what my uncle had contributed then. The problem is now when the family has increased with brother getting married and having a kid,there is lack of room and so we had asked them to give us the permission to go ahead and make another room on the roof which e he simply denied and told him to get a separate apartment fr himself. However we went ahead and made the room without their consent coz as per new riles of corporation one can extend the property by 25% without any legal permission as we are also the owners of da house. I want to knw that sin e we are living here fr da past 40 years and giving all maintenance and everything a nd the owners as well do we have more right to claim the property ? Even a tenant has the right . Kindly advice as what are the provisions that we hv here fr dis. Any help will be much appreciated.