Younger uncle took all property papers and not giving my father to atleast look for.

By August 2015, my grandfather died. After that within 2-3 months my small uncle took all the property papers with him. They are 6 siblings including my father (3 brothers & 3 sisters). My father is the Elder one and look after my grandmother who is paralysed and bedridden. My uncle stays in another flat with his family and my father and second uncle stays in grandfather's house. When my father asks for the property papers to look for, which is still in my grandfather's name my uncle refuses to show or sometimes bring few of the papers. So, one day my father asked him to give the papers so that he can take Xerox of it at least, but he denied. What is the issue we don't know, why is he always refuses to show the papers? Is he trying to mislead with it? Can he sell the property without my father's signature? What legal action can we take for not giving us papers to look for. And if my father wants for partition, will it be equally distributed? As my uncle is paying the property tax and also the money is coming from grandfather's property which he kept for rent. We don't have any property papers with us not even Xerox of it. Please give suggestions.