Dispute over ancestral property claim. What are my legal options ?

My Grandfather mother's (Already has 3(2male+1female) Childrens) has 2 marriages and both are legal. 1st husband already has 2(1male+1female) kids. they does not has their own kids. Under Family settlement 3 home distribute in 3 brothers verbally but not in papers. we are living in our portion from more than 50 years and this is the 4th gen who is living there. my father and grandfather was died 8 years ago and now the step brother of my grandfather wants us to leave from that house. because in property papers there names are mentioned not ours and we are getting only small portion of that house. Is there any widow right on that property?My mother is living there since marriage. As step grandchildren claims on that property also. Or can we Put the case to distribute the ancestral property equally to all sons? if there is no will or power of attorney.In my grandfather govt ids papers, step father name was mentioned but in some property papers there real father name mentioned. suggest