More than anything, that hug relieved Zeus. He'd been worried there was something behind his youngest son's words that he'd been missing. Worried that in his absence, Opportunity too would have fled him. Joined with Hades, or focused on his failings like Athena had.
It was relief to know that he could embrace him, still, and after holding it for a moment he let him go. "Too long, son. Let me look at you. This city agrees with you, you look healthy."