Mother's father died brother fraudulently captured the property

hello iam from pune i want advice regarding my mothers father property. my mother and her 2 sisters 3 brothers total 3 sister 3 brothers. in solapur my mothers father property 1 shopping complex 1 home. in 1984 when my mothers father died. one of my mothers brother.had did wrong thing he convinced his mother to sign the complex property to his name only and he did as mother gifted to his only 1 son and home 1 son. remaning 3 sisters 1 brother nothing got. and that brother taken all 3 sisters signature in blank bond nothing written.that time he told i will give u. now he changed he tells mother given him. so can my mother get share in his father property if she fights. i want advice