1. IF Father has executed a Will and IF children has signed their "No Objection" on the WILL, THEN the will becomes null & void, for all purposes.
2. "ALL" the residual legal heirs of the deceased father, are entitled to EQUAL share in the Fathers property (which includes younger brother).
3. However, younger brother CANNOT sell this property (part /full) without first conducting a "partition proceedings" in the local civil court. No limitation period applicable here.
4. Brother being younger brother, you should consider "amicable settlement" via a registered "Family Settlement Deed", and settle any dispute /issues, forever, more so since, court litigation takes money & time and family relations turn more & more bitter.