It's a ridiculous letter. That letter among many things suggests that Trump might be suffering from worsening cognitive decline. When you watch videos of a much younger Trump talking about something he has a very firm grasp of like real estate development in New York, it's like listening to a different person.
It would be better for the GOP to get on board with the impeachment of Trump. The presidency of the United States is too serious a matter to be left to a rabble-rouser like Trump despite such a person being a skillful manipulator. One of Trump's core skills is speaking persuasively to the masses, protest voters in particular, in a way that pushes their buttons effectively. When Trump appears to speak like a fifth grader, it is no accident. There is a method to his madness. But that obviously does not work with people of sophistication at the level of world leaders. Those people tend to be both book smart, which Trump has never been, but also skilled manipulators having gone through rigorous selection in the politics of their home countries. Trump, particular with progressive cognitive decline, is completely out of depth with that set. Nobody among world leaders respects him. Nobody. When he gave away the store to Kim Jong-un, the world was watching. Erdogan will not dignify his overtures with a response.
The clip of Trump discussing Citizen Kane is always fun to contrast with his current manner of speech.