I'd be very suspicious of any man who is tip toeing around my wife behind my back. If it makes you feel uncomfortable then he needs to know and stop.
However, if you plan to talk to this man, I wouldn't do it without my wife's knowledge. Let her know that you do not intent on making this a big issue or causing disruptions. He just needs to stop. If he wants to encourage her he should do it publicly at the hall. And by that I mean no backroom shenanigans.
You have every right to tell this guy to back off. And make certain they (other elders) understand that it shouldn't have any negative effects on your wife. If you see she is being treated differently, involve the CO.
Good luck