grammar - redundant definite article

I have a colleague who insists on inserting "The" into the following sentence ---

"If you're familiar with Johnson City's hip, comfortable The Ellis Hotel, you'll love the new Autograph Collection by Marriot."

The rationale for inserting "The" is that the hotel is persnickety about their name, and my colleague insists on deferring to the hotel's preferred style.

I maintain that the geographic identifier --- "Johnson City's" --- functions as a definite article, thereby making "The" redundant and grammatically incorrect. I.e., we would never write, "If you're familiar with the hip, comfortable The Ellis Hotel, you'll love . . ."

Is this in fact ungrammatical ? Or is it merely bad writing ?

If the former, what specific rule has been violated ?