Adan Lopez has been exclusively using the original grits for probably over a year now. I've seen him get up and over anything and everything...snow, sand, mud, river crossings, etc. I briefly owned a pair and think they'd be sufficient.
I've looked over the Pure Grit2s and the traction appears better than the originals to me.
I say go for it. While I don't currently own a pair, they're certainly the type of shoe I'd wear up there...maybe just add microspikes if worried about snow.
Better he gets up there in a shoe he likes than try something entirely new just before a trip.