None, to the point that I was seriously wondering if we were meant to think they were angry and not speaking to each other. It was extremely weird.

very weird. although not necessarily any weirder than rose and jack having pretty much no interaction either. like, you know, "omg you're alive and you were dead! wtf!" oh, JE, you make no sense.

I got the impression he came back because he wanted to give the character some closure/show he'd grown and changed for the better, then leave off with him for good.

yes, sensible.