||Often a man will behave completely out of his mind and inappropriately because there is a medical problem. (I have seen this a lot, unfortunately).
If this man who is pursuing you was in the past a decent upstanding gentleman (I don't know) or otherwise observant member of the community and is suddenly out of control and out of his mind (and I think that sexually harassing a Rebbetzin is pretty out there), then perhaps you might be doing his family a very big favour by speaking to his wife, grown son or brother etc that he might be having a medical problem.
There are many many medical situations that would be responsible for uncharacteristic (if it is) behaviour such as you describe.
The first doctor to visit (I think) would be a kidney doctor (endocrinologist). I personally have seen kidney stones (Yes!) cause fine, upstanding, always observant men to become "possessed" by an overwhelming and unreasonable, uncontrollable need that might cause insane, uncharacteristic behaviour such as you describe.
Also there are many medications that one could begin that might have this type of behaviour as a side effect (personally I have heard of endocrine system side effects such as might be responsible for such behaviour as you describe from common blood sugar and cholesterol medications).
Imagine how it might affect this man's life if you alerted a loved one to this fact and it turned out that his cholesterol or blood sugar(ie.) medication only needed to be switched or maybe the root cause was a kidney stone that a laser office visit could change?
Meanwhile, if this man is being so aggressive with a woman such as you, imagine the boosha that is surrounding his whole family and the impact this would have on his children and wife throughout the community?
If it were me, I would find a kind, caring way to speak to a family member and say that "I think your husband, father, brother is having a medical problem that might be very easy to correct"
Again, I feel as though the man who is desperate enough to sexually harrass a Rebbetzin is also endangering himself and his family by frequenting the kind of places where one would contract diseases and other dangers. I would assume that no man in his right mind would do such things, and that there must be an underlying problem that is causing this.
Just felt I had to put my "two cents" in.