Succession rights

My grandmother who died in 2004 had one shop registered on her name. That shop was purchased by my grandfather on her name. My grandfather have one house and one land plot on his name which he has equally divided among his two sons (my father and mu uncle)through unregistered will and mutual consent.. he has two sons and two daughters, daughters have been given movable property but no share in immovable one. However succession of that shop is not clear. It has been forcefully occupied by my cousin (my uncle's son) and he says that our grandmother has gifted it to him however when we checked records with municipality,that property is still on name of grandmother only, also there is no will neither any registered gift deed by grandmother. My grandfather says he is not aware of anything and he cant help. He also indirectly want to support my cousins claim. Please suggest do grandfather have any right of ownership over that shop after my granmother's death or that shop shall be considered under succession law to all legal heirs.Also please advice who shall be considered legal heir of my deceased grandmother..if my grandfather is still alive. Also please suggest rightful action so that all legal succesors get their due right instead of my uncle/cousin. Also please advice how can we register that property on name of all legal sucessors.