A friend of your's who still smokes brings up a good point? Sounds like the friend of yours is looking to pick a fight. Because he is not allowed to smoke during meetings, he has a resentment against those who vape.
If the "self help" meeting is similar to the one's I've been to, not long ago, people packed those "smoke filled rooms" because they were willing to do whatever it takes. One wonders how serious some people are about their recovery to make another person's vaping interfere with that.
I would also like to point out that a mere 10 grams of of eggplant has the same amount of nicotine as a person would receive in over 4 hours of exposure to second hand smoke. Vape contains less nicotine than smoke.
The point is, your "friend" and any "non-smoker" at your meetings is exposed to more nicotine in the course of their daily lives than they are close to being exposed for the 1 hour at your meeting.
Nicotine is a naturally occurring substance in many vegetables.
The Nicotine Content of Vegetables
Personally I would feel that vaping at a meeting is an outside issue, and if there was ever a business meeting in which that was discussed, I would mention this.
I think several members of your meeting need to perform their own inventory and not look for reasons to hold resentments towards other people at your meeting.
At the self help meetings I attend, the motto "Live and Let Live" is displayed predominantly. Perhaps some people in your meetings need to be reminded of that.