Unequal division of property among brothers how to get equal share

My father built a house and registered in the name of my mother. Its area around 35x45 Sq.ft. next to National highway worth 80lacs. during allotment she proposed 35x30 (frontside , towards road- commercial)constructed house to my younger brother. for me 10x25 constructed house balance is passage and others. main reason is he is uneducated and im educated and earning. my earnings also max 30000/month. he is earning 7000/month. is it valid if she only signs will or registration. both brothers married and i have 2 children(1boy and 1girl). we have one elder sistr also.Thank you for ur service