Owner ship of grandfather house

Hello I am staying at my grandfather house but my daddy elder brother have put his name in the house as he was big after the death of my grandfather and he has also put his son's name in the house and the will Power of attorney, that whole house will be only his son's, but me and my mother are staying in the house and my mother is staying from 43 years, we also have id and address proof of same address, so what legal action we can take , becaus they are telling us to go from here , and they are not ready to give any money or another house, so what we can do , kindly suggest