From what little I know and have read of this guy, the basis of his dissatisfaction seems to be that his man has not shut down the courts that are standing in the way of his anti-immigration plans("promises" ). Actually a further deviation from reality.

I can see a sacking happening.

Carlson's ONLY motivation is that Trump hasn't kept his campaign promises ...

"His chief promises were that he would build the wall, defund Planned Parenthood, and repeal Obamacare, and he hasn’t done any of those things,” Carlson said.

He was always willing to overlook Trump's narcissism, greed, and resistance to facts because he thought Trump could ram through the conservative objectives. Carlson has only changed his mind about whether Trump could get the job job. Not about what job he wants done.

Whatever Tucker says, he's still a putz.

There is no reality on fox. Doesn't exist.

You know a republican is on his/her last legs when Fox "News" turns on him/her.

The bubble is leaking.

Tucker says that Trump is incapable of handling the job of president. That is contrary to the typical FOX propaganda byline. However, Tucker goes on to say Trump's role is to ask the important questions and begin the dialogue. That is also contrary to what we know about Trumo and his followers. They do not engage in meaningful dialogue. They refer back to anecdotal evidence (non-evidence, aka: fiction, made up hyperbolic hyper-irrationality) to support their position. They compensate for the inability to actually succeed in maintaining a logical argument by speaking faster, speaking louder, talking over and interrupting continually, and obfuscating or quickly pivoting to a nonsequiter. So while Tucker made some headway in returning from the darkside, it was only temporary and he'll be back to perpetuating his propaganda tomorrow.