First off, as a mom of a preemie,>27weeker< my hearts go out to this family. It's a long and rough road, even as they grow older. 
Secondly, have the family contact the "March of Dimes" to see if they have a chapter in that area, and if they do..they can offer some help.  Even if the hospital can get preemie diapers, they are going to be really big on the baby for a good while. I'm not familliar with that country, but if they have a 
walmart ...they tend to carry a good deal of preemie clothing. If not, babies r us >as already mentioned< carries them, I got some stuff from this site 
http://www.preemiestore.com/Micro-1-4-lbs_c_3.html.
I would have your friend check to see if they are going to allow the baby to be in clothes before spending the money on preemie sizes. As mentioned, they dont normally want them in clothing to interfere in monitors or in case something happens they need to access the baby quickly.  Otherwise, just do a websearch for preemie clothes or preemie supplies and you'll find a ton. Many offer free shipping. For diapers, contact "pampers" and "huggies" directly, tell them the situation and i bet they'll send a package or 2 preemie sized diapers out to them. 
Here's the link to the March of Dimes, contact them and see what they have available for that area if none, perhaps they have ties with someone who can help
http://www.marchofdimes.com/default.html
Best of luck to the family and the wee one.