Deathbed Will Change

[Bob Barilla]

I've been listed as the executor and personal property heir (vero beach, fl condo) on estranged fathers will for 15 years. He found out he was dying (passed last week) and changed his will to give me, his niece and nephew each 33%. He made his niece the executor. Any recourse and/ or how can I ensure everything is done legally? Thanks.