Eric's first feeling when he saw Dom was shock and surprise, followed by a happiness when confirmed this really was Dom - even if it wasn't the same Dom, it was some version of him. Some version that they could get to know again, even if it would never be the same. He chuckled when Dom pointed out that he was dressed. Apparently that version of himself wasn't too different from him.
Everything changed the next moment though. First Dom said that the Sam of his dimension was dead, which was enough to wipe any smile of his face, but then Kensi hurried out looking anything but happy about this. In the awkwardness of her departure, he watched the door she'd left through, then turned back to Dom with a smile on his lips. "The clothes are less than optional," he joked, as if Kensi hadn't just left. "I realise you're not the Dom I knew, but it's still great to see you. I look forward to getting to know you."