Well, I certainly wouldn't call it "bluegrass..." This is the guy's take on the contemporary style of using a lot of tapping and pounding on the instrument. Tommy Emmanuel is likely the current master of this.
Actually, I'd rate this fellow's technique as.... Adequate. His left hand technique is pretty rudimentary; he's mostly using thumb and finger to hold a barre of sorts and then fingering a few other notes, and he apparently doesn't use his little finger at all.
Nothing in the way of advanced chording and tones like Emmanuel uses.
Also....Something that drives me a little nuts....He constantly lets his left hand shoot up to an upper-fret position...But he doesn't finger any notes there. He's just moving his hand a lot so it looks cool...
Just a pet peeve of mine... I've watched folks do this for years.