Originally posted by whatsthisbuttondo Just tell him like it is ridicule his examples of better work he will soon dissapear hopefully a bit wiser
I don't know that I would resort to ridicule. It would be pretty gratifying to point out compositional and post processing errors in his work and use your own photos to demonstrate how things could be done better, but that probably would be treating him in the same vein that he has treated you.
Probably better to just blandly say "very nice," and let it go. No sense engendering bad feelings over someone else's poor perception of their own photography.
Edit: I think I missed the part where he was making comments on photos on Facebook. A lot would depend on whether you want to preserve some sort of relationship. Certainly the easiest thing would be to make critical (but constructive comments) on multiple of his photos. A couple of days of that would certainly fix the situation. Probably the less inflammatory thing to do would be to block/unfriend him.