The circle of jerks, that is the Washington political press that goes whichever way the lefty talking points blow in their quest for conventional wisdom, do not really care about a White House staffer's statement about John McCain in a private meeting. This is the same circle of jerks that was willing to push out Democratic hits against John McCain for being old, etc. in 2008. They really don't care. They are just trying to man the furnace of the outrage machine that drives clicks and churns profit.
Look, here's my quick take on the whole thing: it was a private meeting where Kelly Sadler stated the obvious truth too bluntly. John McCain is going to die and he is not going to go back to the Senate. That's a statement of fact. But, based on press reports, it seems Sadler was not just stating that fact, but casting it out insultingly. That is unfortunate and ghoulish, if true, but this White House is presided over by a man who insulted McCain for saying he didn't like men who were captured.
Trump set the tone and Sadler just fits in. This is neither new nor worth getting outraged about. This story has only lasted as long as it has to distract from the President successfully moving the embassy to Jerusalem and successfully getting North Korea to proceed towards serious talks.
The real story here is that White House staffers are leaking to undermine each other, for giggles, and seem to have no idea how to behave to support their President. Likewise, I'm sure some is malicious to undermine the White House. That is the real story. Paragons of conventional wisdom within the circle of jerks may think otherwise, but it is the story. This White House, after more than a year, still leaks in ways that undermine its mission and messaging and these leaks are coming from a communications team.
The McCain stuff really isn't anything out of the ordinary for this White House. Of course, neither are the leaks. But the latter is the real problem.