YWBTA, but to be honest I would 100% do it if I didnt like him. Hes already made a known creep of himself without your help, and then been incredibly sloppy. With the addition of his reddit account he will become a legendary story to tell for years. Make sure you screenshot everything asap, once this gets out he'll delete it all.

Just because it's the asshole thing to do doesnt mean I advise against it. Just as long as you have no illusions about taking the high road or moral superiority I will give you my blessing.

I've always found self-humiliation to be one of the most delicious and elegant forms of humor. Hopefully he will see it that way. Your portion of embarrassment will be that you are a jerk. If you acknowledge that, nobody can judge you.