George T. Conway III is a lawyer. He happensto be married to Kellyanne Conway, Trump’s Close aide.

He writes in The Atlantic that Trump is unfit to serve.

It is no secret.

He writes:

No president in recent memory—and likely no president ever—has prompted more discussion about his mental stability and connection with reality. Trump’s former chief of staff John Kelly is said to have described him as “unhinged,” and “off the rails,” and to have called the White House “Crazytown” because of Trump’s unbalanced state. Trump’s former deputy attorney general, Rod Rosenstein, once reportedly discussed recruiting Cabinet members to invoke the Twenty-Fifth Amendment, the Constitution’s provision addressing presidential disability, including mental disability…
Rosenstein denies that claim, but it is not the only such account. A senior administration official, writing anonymously in The New York Times last September, described how, “given the instability many witnessed, there were early whispers within the cabinet of invoking the 25th Amendment”—but “no one wanted to precipitate a constitutional crisis.” And NBC News last week quoted someone familiar with current discussions in the White House warning that there is “increasing wariness that, as this impeachment inquiry drags out, the likelihood increases that the president could respond erratically and become ‘unmanageable.’” In September, a former White House official offered a similar assessment to a Business Insider reporter: “No one knows what to expect from him anymore,” because “his mood changes from one minute to the next based on some headline or tweet, and the next thing you know his entire schedule gets tossed out the window. He’s losing his shit….” 
The president isn’t simply volatile and erratic, however—he’s also incapable of consistently telling the truth. Those who work closely with him, and who aren’t in denial, must deal with Trump’s lying about serious matters virtually every day. But as one former official put it, they “are used to the president saying things that aren’t true,” and have inured themselves to it. Trump’s own former communications director Anthony Scaramucci has on multiple occasions described Trump as a liar, once saying, “We … know he’s telling lies,” so “if you want me to say he’s a liar, I’m happy to say he’s a liar.” He went on to address Trump directly: “You should probably dial down the lying because you don’t need to … So dial that down, and you’ll be doing a lot better….”
Behavior like this is unusual, a point that journalists across the political spectrum have made. “This is not normal,” Megan McArdle wrote in late August. “And I don’t mean that as in, ‘Trump is violating the shibboleths of the Washington establishment.’ I mean that as in, ‘This is not normal for a functioning adult.’” James Fallows observed, also in August, that Trump is having “episodes of what would be called outright lunacy, if they occurred in any other setting,” and that if he “were in virtually any other position of responsibility, action would already be under way to remove him from that role.”