Oh Mike, my heart hurts for you. I cannot imagine being in your "shoes" so soon after losing a beloved. While not legal, I think pulling that concealed weapon would have been appropriate- at least to shoot off a toe. I have never been in that position, and even if I ever was, I still couldn't fathom your hurt. I handle things one of two ways and neither are particularly useful or healthy. I would either hold in my feelings and walk away hurting, or I would unleash the righteous wrath I was feeling.
I hope that the Lab dude realizes the hurt that his selfish, inappropriate and stupid comments caused - "friends" like that cause more pain than they are worth. Sending healing
One last thought - You can cure ignorance through education , but STUPID IS TERMINAL. That dude is just plain and simply dog stupid.