Interestingly, I read a story over Pesach regarding this topic, where someone’s son had a miraculous recovery after he undertook to stop talking during davening. (The father’s name is listed at the end, and it was supposedly heard first-hand).
The article was in Yiddish in Dee Tzieitung/News Report, on page 20 of the Yiddishe Tzeit/Torah section – in their Pesach issue. It’s reprinted (and perhaps translated from Hebrew) from what they refer to as ????? ????? ??? ????? (I’ve never seen it, but perhaps you can figure it out) and titled ???? ???? ??? ???? ???? ?????????.
I thought you might consider sending the Rabbi a copy of the article or something similar instead of getting too “in your face” regarding his Shul. And if you want to take it a step further, you can suggest/ request that a “no talking” campaign be made in his Shul beZchus a Refuah for someone known to the Mespallelim. Just make sure to write respectfully without mentioning specifics, and maybe even increase your check…
Just my two cents.
It’s nice that you care and want to do something positive to hopefully effect change.
Hatzlacha!