He's only inadequate if he feels in his heart that he's inadequate. His feelings don't matter when it comes to what she says or did. They do matter however if he feels inadequate or if someone told him he was inadequate. Anger toward his ex-wife isn't going to help him get beyond feeling inadequate. As far as he is concerned, he's through with her.
I don't know why we as human being need to feel inadequate just because someone said we were. I, quite frankly don't know what he's feeling, but if he's crawling around in a deep depression in his life, he needs to seek help, otherwise, he should just forget about her, carry on with his life, and remain happy.