Lindsey Electric Guitar Technique

[AlexD]

Question about how Lindsey plays the electric guitar:

When Lindsey does the thing where he is "flicking" down on a string to play a note with his right hand, he mutes the string above with his right hand thumb. But does he mute the string below it using his left hand or is his right hand accurate enough to where he doesn't need to mute it? Sorry if that's confusing.