John McCain, obsessed with playing the 'POW' card. He did his duty with honor, there is no question of that. But the fact that he keeps bringing it up to use it as a shield, detracts from the respect he would otherwise get.
Most real heroes that I know, never mention it. To talk about it, takes away from the experience somehow.
And I certainly agree that McCain's time would be much better spent with his family, than screwing around with Trump and worrying about legislation that should be meaningless to him, since he will not be around to see how it all plays out.
I believe that McCain doesn't want to step down because by doing so he would have to face the reality of his situation. He is in denial. He believes that if everything is normal, and he goes to work every day, and such like that, then there is no real problem. He seems to be denying and avoiding reality.