I'm confused (big surprise) what exactly did he say? It looked like he was signing to another person off camera, you could see their hands on the
lower left of screen. I wish there was a subtitle. I saw the one comment that gave a "translation" but was that a joke or real?
I'm not sure what your point is, OP, but a big part of American Sign Language is rather emphasized facial expressions on the part of the signer.
From the little I know, he was relaying what the speaker was saying. NYC has a big deaf population and I'm sure they're grateful to have signing
including in the news conferences.