The Ruling on Divorce in Terms of Its Occurrence or Non-Occurrence

What is the ruling on divorce in terms of its occurrence or non-occurrence in the following case: A man said to his wife's brother, "Go to her and tell her that if she does not do such-and-such, she is divorced." So he entered the room but did not inform her, then he left.So he said to the husband: She refuses to do what he says—Meaning: "If she does not do such-and-such, she is divorced"—and she did not do it, and he did not inform her, meaning he lied to her. So the husband left the house and did not say anything?
The divorce does not take effect in this case; because the woman was not informed. If she leaves off doing what the husband said at the time he specified, while she is unaware of it, then there is no divorce upon the husband, and there is no oath upon him either.