You might not want to hear this, but it's standard tuning. He's using the open E strings (both low and high) to create a nice drone. Starts out with just and E (022100) alternating with E6 (022120). When he goes to the up-and-down the neck part, he's being very careful to keep the melody note on the G string which allows him to use both E strings as well as the open B to create the chord harmony. Play along with it and you'll see.
Hope this helps. And welcome to Guitar Noise, by the way. Looking forward to seeing you around on the boards.