Just to reiterate what several others have said, find out where he’s headed and what his basic mission will be. If he’s going to be humping all over the place, weight will be a big deal, but if he’s mounted, weight won’t be that big of an issue. Just remember that form needs to follow function.
I got back from Al Anbar about three months ago. All my time outside the wire was in CLPs (Combat Logistical Patrols – aka convoys) riding in UAHs and MRAPs. I carried a Busse Ripper in a Spec-Ops sheath. Having the big knife on my leg was nice, but truthfully, I don’t think it ever came out on any of the CLPs. I did use it in the FOBs to make terrain models, pop open MRE boxes, dig out tent stakes, etc.
Anyway, any Busse over there is better then not having a Busse over there…