Most Helpful Guy
You indeed have a good reason to be concerned. Cowgirls in bikini and alcohol don't make a good mix on guys.
Well, send him some text (even if he said he will not answer). But don't spam him or he will not spend good time (with the cowgirls in bikini) in the festival.
Most Helpful Girl
If you trust him, then you shouldn't worry about those girls because he would do the right thing and tell them to take a hike if they tried anything.