FREE ADVICE FROM A THERAPIST TO ME TO YOU:

My late maternal grandmother used to make very inappropriate comments, and when I was in eating disorder therapy, I asked the group leader what I should do if she commented on my weight when I saw her at my sister's wedding. The therapist suggested several responses, but the one that stuck with me was "That's an interesting thing to say at a wedding." I've used that (adapted for setting) so many times with inappropriate people.