Two generations of wills, which takes presidence?

I am asking this on behalf of a friend's wife. Grandma died and left everything to her two daughters One daughter (my friend's mother) was made executor of the will. Her sister was to receive half of the money if or when anything was sold. Mom was greedy and chose not to sell anything. Now mom has died and left everything to my friend's wife and her brother. Does her aunt still have a claim for half of anything they sell? Grandma's will says the aunt cannot force the sell of anything.