Validity of power of attorney after death

Hi, my father passed away recently in India and my late mothers nephew says he has power of attorney of my fathers property and since i came back from cremation he has taken the locks of the gate that i placed on their and put his own locks on it. He also has possession of all relevant paperwork to do with the house. I have asked if he will put everything into my brother and my names and he said he would but since returning he has not done so, I am travelling back with my brother next week and a little concerned. We have my fathers will here in England which states that we inheriate every thing. My uncle keeps going on about he has power of attorney. Does it not cease with my fathers death, as in england and other countries power of attorney is only valid whilst the father is alive. I am sure he has no legal right in this and is delaying things for some reason thinking that we are not coming back since father passed. He is not very helpful and keeping all documents. I am hindu