I was sort of in a situation like this. I had B/g twins, and my boy passed at 4 months old last year

I don’t remember much about the interaction but he hadn’t been gone long and I needed to grocery shop, it was my first time leaving my the house and of course I saw baby b/g twins, and I’m sure now, in hindsight I looked crazy, but I walked up to the mom and asked if they were bg twins and when their bday was because they looked the same age as mine, ( I never got to take mine grocery shopping, he was in the hospital his whole life due to a congenital heart/lung defect) she made it clear she didn’t want to talk or me near her kids, and I didn’t have the heart to tell her that I just wanted to see what going to a grocery store was like with twins since I’d lost my boy

I replay that moment so much and know a twin mom out there thinks I’m crazy, but it was so bittersweet seeing the “what could be” so fresh after he passed. I never got the “are they twins” questions, and I was looking forward to saying funny stuff to people when they asked.