I think telling may look good on paper, however it would be impossible to predict what would happen next. No matter how many scripts you write for it, the results will be out of your control. It may be an extreme idea, but what if the lady committed suicide upon receiving your news, however kindly meant?
So, no, don't take that risk.
Also, imho, since it involves a senior (to you) person at your place of employment, I can see this backfiring on you in a big way, as mentioned up thread. You would be the one committing suicide, professional suicide. So, no, don't take that risk. Even if he is a nasty b@st@rd at work and you are tempted to have revenge: this just way out of scale for that sort of pissing match.
I agree with you, SGB; she could also be a narcissist that treats people as props who need to conform to her template for living. If you do have "interesting social dynamics" with people, (I am not saying that you do), WouldYouTell, I wouldn't do anything that would shout it out so loud and clear as butting into peoples' private lives would demonstrate. So, no, don't take that risk.