Interesting history here. Barron Hilton actually contested the will of his Father who was going to put all his money into a Foundation. Barron Hilton prevailed and got control of the hotel chain.
I don’t know what would be the basis of contesting this will, but as you observed Barron Hilton did it. He may have a good case that the heirs are bums, but that may not hold once it gets to court.