The property that belongs to your paternal uncle shall automatically pass on to his class I legal heirs considering his wife and children.
In the absence of his children, the properties shall devolve on his wife.
Once the property vests on his wife after his lifetime, it becomes her own and absolute property.
Neither you nor anyone has any rights on it during her lifetime.
You cannot claim any rights in it including the rights to purchase the property in her possession even though it is your ancestral property, because they also have equal rights in the ancestral property similar to you.