Do i have the ability to contest my fathers due to his ex-wife still be named the executor

my father had a will made 5 years after he divorced his wife. they then broke it off completely just a few short years later. But my daddy not being as articulated as some didnt really know how to go about making changes. at any rate, they have now been divorced 23 years now and his ex-wife has been remarried for 15 of those 23 years. Can his will be contested? I didnt know that she actually had possession of the will.