I'm a teacher, and I will be making the following announcement to all my classes tomorrow:

[alcibiades_mystery]

70. Well

I already noted that a descriptivist position would say just that. Yes, if it "sounds right," it's likely because the language has been transformed by sufficient "incorrect" usage such that it loses its "incorrectness." This is neither a new nor an interesting position. So, even though "Himself brought coal to Newcastle" sounds incorrect, and, while it is structurally equivalent to "Neither myself nor my staff did X...," we can still assume that the second will "sound right" to some subset of people, and perhaps one day in the future "Himself brought coal to Newcastle" will also sound right, and etc.

Language is fluid, and blah blah blah. Of course. Yes. Obviously. We all know this.

Here's the problem, in this particular case, if we get off the navel-gazing. In this particular case, we have a teacher issuing what might be considered in some areas a controversial public statement, and one element of it is "incorrect" according to existing understandings of grammar that might be held by the readers. If you showed it to a grammarian, he or she would say, well, yes, that's an incorrect usage of a reflexive pronoun - and certainly not an emphatic, your first failed argument (though, obviously, incorrect only according to existing usage standards that might change, blah blah blah). So, what happens, concretely? The parents who oppose the statement or find it to be a political overstepping of bounds say "I mean, geez, this is a teacher, and he can't even use proper standard English? What is happening to our education system? Teachers issue political statements, but can't teach our kids proper grammar!" And what are you going to say then? Oh, but there is no "standard!" What do you mean by "proper?"

Well, good luck with that, because you just lost the substantive argument to bigoted, homophobic parents, all because the grammar went wrong and you tried to defend it with obscure arguments that make sense to grammarians, but not parents of high school kids. Tell those parents you don't care about "correct usage" because language is fluid. I wish you the best in that endeavor. The problem, put plainly, is not merely grammatical but rhetorical: it costs you way too much to be engaging in arguments about the changing nature of language; you should be engaging the substance.

As for the OP, it costs him nothing to use what currently stands as standard English. If one is issuing a public statement in an educational setting, that public statement should probably use that standard unless there is a rhetorical need not to do so. A public statement on the value of African American Vernacular English, for example, might use AAVE to demonstrate its value. That's fine: the substance and its expression are one and the same. In this case, you lose immediately to the one conservative parent that points out the incorrect usage. It's a silly place to mount to argument for fluid language when so much is otherwise at stake.