your pb choice is a+. they unfortunately share a similar trauma...but i don't really know if that's a way to connect them without it being through some kind of grief group? they're close in age though, hmm. maybe a random connection when he first got to boston on a day when they both needed a little win and they, i don't know, shared a coffee or something and a chat? and it could've turned into a tiny tradition of sorts? OR something different if this doesn't strike your fancy!