He's got a lovely quality to his baritone.
The man’s use of support displays a level of classical training and his long sustained notes show he’s probably in practice. Although he stands looking at the piano, it does not look like there’s any sheet music there, so the song is probably from his repertoire.
The pianist is also very impressive. Not only is he playing from memory, but he stays with this singer, with whom he’d never worked before. The changing tempo (when the music slows at the end of each phrase) seems like a mistake, but it is really a way for the pianist to make sure the singer is with him. This is much harder to do than it sounds, and it would have been fixed had the two been afforded a chance to practice together once or twice.