No one is entitled to inherit anything. Your father could have left everything to the local animal shelter and there would have been nothing you could do about it. My friend’s father promised a certain equity account would go to her, but he left it up to her stepmother to administer it. She died a year later and her kids from her previous marriage got everything, even though my friend had a letter from her Dad stating his wishes. It sucks, but that’s how it works. Knowing your Dad’s past attitudes, nobody should have expected anything. Good for you for honoring your Mom’s wishes, though.