How often is he folding to cbets? It's not that clear, as you say he likes to call but you also say when he called your cbets you were giving up which seems to imply that when he called he had something.

Hand 1: This just doesn't make much sense at all, the way he played out the hand makes me feel like he was afraid of a 4th card coming out for the straight, and wanted to play low variance. Still, I agree this really doesn't make too much sense as a bluff either but I call because I don't feel like i can make a very good assesment of what he has.

Hand 2: Pretty clear fold. I play rest the same.

Hand 3: Another pretty clear fold.