One of the resons you quoted why we do not tell an avel or choleh to sit on Daf 27 was
"The RAMBAM has an entirely different explanation. He explains that the second statement of Rebbi Yochanan has nothing to do with his first statement. Rather, anytime an Avel or Choleh is standing we do not tell him "sit down," because the word "Shev" ("sit") can be interpreted to mean "return," and it would sound as though we are saying to the Avel, "Return to your state of mourning," or to the Choleh, "Return to your illness!" We do
not tell them "sit" so that it not be misinterpreted as being rude."
Does this only apply when one says it in loshon hakodesh - "shev", as that word can have dual meaning. However "sit" in the english language (or any other equivalent translation) appears to specifclly mean "sit", and not "Return to your state of mourning," or to the Choleh, "Return to your illness!""
Excellent question. After writing the above Insight, we noticed that we did not write over the Rambam accurately. The Rambam does not say that "Shev" ("sit") might be misinterpreted to mean "return" (because even in the Hebrew language, the word "Shev" has to be pronounced "Shuv" in order to mean "return"). Rather, the Rambam says that by saying "Shev," it might sound like we are telling the Avel or the Choleh to "sit down in your Aveilus" or to "sit down in your illness," which implies that we are telling him to return to that state.
Accordingly, this would apply in other languages as well. Indeed, in English we say that an Avel is "getting up" from his Shiva on such and such a day. Thus, if we tell him to "sit down," it might sound like we are telling him not to get up from his Shiva, but to remain in his state of sitting Shiva.
All the best,
Yisrael Shaw