Inherited or ancenstral property defnition

Hello Experts,

   I would like to know the defnitions of Inhertited property/Ancenstral defnition,

my Grand father [Mother's Father] has acquired some property on his name,my mother is the only child for him,my father expired ,we are three brothers 

and we have a son each.my grand father divided the property into five sections [non-registered agrement]

its a mutual understanding with in the family ,we are cultivating lands as per his wish from 2007.

Question ::

        Will my son or my wife  has got any right on my property which was given to me by my grand father property? or since my mother is the only child to my grandfather and my father is not alive she can overwrite what ever my grand father said, as its not a registered will?? my father does not have any property with him,

Thanks,

Nitin.