It’s not fluoride poisoning. You’re asking for something you’re assuming is the issue before understanding the problem. I think that fluoridation was useful when it was needed as oral health would have suffered and not having it wouldn’t have been better. Now the science is shifting and instead of assuming you know, just read something or watch a doctor talk. Maybe your friend isn’t the one to be fighting for water fluoridation. And maybe, just maybe, you are both not knowledgeable in the subject. I’m not either! That’s why I listen to doctors who present the science clearly and correctly (and without a monetary interest!).
NutritionFacts.org - Why I Changed My Mind on Water Fluoridation