I'm unaware of
anywhere in the US that moccasins are actually common. (Including on the rez other than regalia in ceremonies, actually.) So that seems unlikely, from a cultural aspect, for your character. Many
slippers are
moccasin-like, often lined with (synthetic) sheepskin, but that's all I can think of.
Military guys seem to just wear their running shoes when they need something comfortable or somewhat destructible off-duty. And the Special Guys all wore
trail runners or mid-height trail shoes when I was in Africa (I still have my
Keen Voyageurs) but that's probably because mud was not a serious threat where I was in Africa. Deep mud would suck those right off of your feet. (This is the main advantage of boots- that they don't come off in mud.)
If he's seriously into the Latin American thing, how about
huaraches? Or,
huaraches? :) I have a pair of the latter and find them rather handy- easy to pack in a backpack, since they are flat and take up little volume. They're both more Mexican than Central American, though a quick google of "Guatemalan shoes" shows something essentially identical to the former. Neither is really what I would call combat footwear, though.