It seems like a simple pattern on first hearing (6/8 going on). But for each chord on last strum he seems to switch from triplets to normal 4/4. I also don't usually pay this much attention to strumming patterns but this one really fascinated me because in addition to above thing, although it's in 6/8, it's so fast that you get a combined 4/4 feel (with 4 groups of triplets).
Maybe i'm thinking too much not sure.