I have one doubt whether my father's brother son can claim right of the property based on the original property belonged to my grandfather and that too not my grandfather's self earned property. As mentioned earlier my grandfather got the property as a share from great grand father. ie ancestral property.
Your father's brother son cannot claim a share based on his grandfather's property now because your grandfather has properly distributed the property to his sons as per his desire and choice, that too legally.
Though it was not your grandfather's self acquired property since he distributed the same to his sons during his lifetime, there is no question of ancestral property as per law, hence your cousin cannot stake any claim in the property in any manner and it will not be maintainable.