Is the land that was granted as compensation for the room built by the questioner's father before his marriage, and in which his grandfather later resided after selling the family home, considered the exclusive property of the questioner and his father, or do his uncles residing abroad have a right to it?

If your father built his room on land not owned by anyone and took possession of it through construction, then this is considered a legitimate acquisition by which he owns the spot and is entitled to it exclusively, unlike other family members. Whoever possesses a property for ten years, and the disputant is aware and present and did not object, then he has no right to object later. If your uncles knew about the construction of the room and did not object at that time, then they have no right now; as their silence is considered an acknowledgment of their brother's ownership of the land and the room, and any compensation for the room follows its ownership.