Honestly, Nick found it hard to not notice how obvious it was that his step-sister's boyfriend was into guys. No matter how hard he tried, at first for her benefit, he couldn't avoid seeing Caspar's eyes lingering on his body ---- or lingering on the body of any attractive male in their presence, and while Nick had, at first, saw ignoring it as the best method for Circe's wellbeing, he was now actively going against that. If his step-sister wasn't bright enough to see that she was dating someone who'd rather sit on a cock, then Nick would show her; vividly.
So, no; it wasn't out of good will or an attempt at creating a bond that he was pushing a second beer into Caspar's hand, both of them on the living room couch. It was Nick trying to prove something.