I'm posting here primarily to prompt replies from those on this forum who are hardcore painters, but in lieu of that, I'll help as best I can.
Do you have a hobby shop in your area? I would start there as they would carry the supplies/equipment and could suggest what modelling stuff he would need. You can also look up Tamiya paint online and get spray primer and some basic colors for camouflage. I don't use an airbrush so I can't help you there…but a hobby store person could. Be sneaky and find out if he likes standard model paint or water-based paint. I like the latter so I use acrylics…but I fall outside the norm. Flocking stuff might be good too for using on the base…if he's inclined that way.
Also, I suggest a good glue. If he's a modeller, then Testors modelling glue, or something compatible would work. I use superglue as it's faster and quite strong. If you get superglue, then there are good options like flexible squeeze containers that you can replace the tube in, or gel (handy), or even w/ a brush applicator.
Any art store will carry brushes. I'd go for a range of very fine up to something 1/2" wide. Shape options are always good. Pointy and flat are two that work best for me.
Modelling putty is also good if he likes to modify things.
Hope that helps! Good luck and maybe someone will come on here and offer you some even better suggestions.