Dear Client,
In the Present Scenario, your grandfather and his brother had jointly owned a plot of land, with an unregistered agreement, in the year 1982. Your grandfather's brother had subsequently relinquished his rights to one plot, that was occupied by your father and his brother. However, here, the Jamabandi still states your grandfather’s brother’s sons, who are presently claiming ownership on the land. Now, despite the agreement, since the same was not registered, their names are legally recognized unless the same is removed legally from the authorised documents. Further, your family may claim for adverse possession on the land, if they had continuously occupied the land for more than 12 years according to the Indian Law. But, to remove their names legally, you may approach the Revenue Department or even file a suit in the court. However, you may establish your ownership over the land, and update the land records if you had a continuous possession since 1982.
Hope you find this answer beneficial for resolving the dispute.