It was certainly less awkward when Zerxus was half unconscious, rather than an inch away from his face. Bruce isn't exactly broadcasting a lot of emotion, but it's a rather closer look into his eyes and micro-expressions than he wants.

Especially when the desire for Zerxus to be able to rest is still a thing he (nearly against his will) wants.

There's a second or two of awkward, then he remembers that he had a 'plan' for this, before his father got... smugly amused. He slides his fingers into Zerxus' hair and kisses him. Slowly, deeply, and even warmly.

Primary objective, truthfully? Affection and getting this asshole to stop looking at him.