Just a comment on size, IMO an RD6 or RD7 are great, tough knives, but length-wise they are a lot of steel for the typical soldier from what I hear from recent family/friends who have deployed. Of course, the individual should get what he wants or what works for his job, but as Blue Falcon said, "I don't know of any task in country that would require your cousin to need a long bladed knife past utilitarian size." That is consistent with what I hear. Most soldiers are using knives for everyday tasks and for that, it seems like something in the range of 3.5" to 5" range is plenty, plus it's lighter and easier to use for utilitarian detail tasks.
An excellent example of a utilitarian knife of this sort would be something like the ESEE 4, the new Swamp Rat Rodent 4, or the Swamp Rat Ratmandu. All of these knives weigh in at around half a pound (without sheath), and are much easier to control for utility cutting tasks. I own the Ratmandu, but honestly, if I were young enough to be deploying in the service today, I'd probably take an even lighter 4" blade, like the Rodent 4 or ESEE 4.