Can i claim my right again

We r 3 brother nd one sister ,my father had two properties when he died 20 years ago.one was his name nd other was perhaps both mother nd father name ,both r earned by himas mother was uneducated nd housewife.after my father's death our two elder brother convence me nd my younger brother who was just 18 at that time to sign papers nd nd register one property to their joint name ,nd one property on mother's name . they convence me that when he will me more mature we will give that to younger one.but now they not giving him .they convence mother to got one ,one shop from it.my mother is very old nd influence by them nd also orthodox who belive that property belong to sons only. else after i signed papers they never gave me anything nor i got any dowery as my marriage was love and arrange marriage.. they change a lot. me nd my brother r feeling now he has no choice of getting equal share nd i'm out as they r not even talk about it. i'm feeling cheted. i have two question 1. is my mother can give propry or portion without others concent as it was originaly father's property. can we claim relinqish property again