What does the figurative expression "the dead would commence to rocking with the beat" tell readers about Lemon's talent as a blues musician?

The figurative expression "the dead would commence to rocking with the beat" tell readers about Lemon's talent as a blues musician as a result of the extra ordinary talent Lemon had in waxing rythmns and words together leading to great songs.

It shows that, Lemon was an extraordinary singer, that, no matter who you are, you would definitely key into his songs vibes when being played.