Trump, Comey, and a Point of Grammar, a Point of Style

While I greatly appreciate you informing me, 

on three separate occasions, 

that I am not under investigation, 

I nevertheless concur with the judgment 

of the Department of Justice  that 

you are not able to effectively lead the Bureau.   * * *

 I wish you the best of luck in your future endeavors, 

— Donald J. Trump [to James Comey, 9 May 2017]  

Note the introductory clause to a key sentence in Donald Trump's brief letter firing Mr. Comey: “While I greatly appreciate you informing me [...] that I am not under investigation, [...]." On that clause: 

          (1) It's unnecessary. 
          (2) It's unsupported. 
          (3) It's part of a "shit-sandwich" structure of the traditional Bad News Communication, with a compliment near the beginning and an upbeat end to the letter: here reduced to "best of luck" at the very end. 
          (4) It's ungrammatical, or at least questionable for a formal document: the "you" should be "your," the possessive, giving "your informing me." Mr. Trump doesn't so much appreciate Mr. Comey as he does Mr. Comey's action in informing him that he, Donald Trump, isn't "under investigation" — if that happened, which is a question of fact, not language usage.  

           (To elaborate: The issue, in old-fashioned terms, is whether to use the possessive case ["genitive'] with an "ing-form" acting as a noun [a gerund], or the object case ["accusative"]. The venerable William Strunk and blessed E. B. White apparently suggested this test: "Do you mind me asking you a question?" or "Do you mind my asking you a question?" In the first possibility, the question would be if you'd be mildly bothered with me, in the second, it would be my action. In the Trump-letter case, it'd be «I appreciate you, because you informed me [...] that I am not under investigation» OR, what I think is the intention, «I appreciate your {act of} informing me [...], that I am not under investigation.» In informal usage, it would be perfectly correct to say, «Hey, Jimmy: I really like you letting me know the Feds aren't» — or "ain't" — «on my case.»)

Note also the final clause,  "[...] you are not able to effectively lead the Bureau." 
          Now, it's perfectly grammatical and generally okay to (unobtrusively) split an infinitive, but there's no particular reason to do so here; and keeping the infinitive together yields, "you are not able to lead the Bureau effectively." Usually, nouns outrank modifiers, but it would help drive home the point to climax the sentence with "effectively."

So let me bet a $100 monetary contribution to the ACLU that this sentence is a Trump Family writing contribution: Mr. Trump or his kinfolk or small circle of political operatives produced that one, with only minimal vetting — as in proofreading — by professionals (e.g., a word person other than Sean Spicer).