I'm currently in Kosovo, been here since June. Where in the country is his house, do you know?
The infrastructure here is very much 3rd world. Especially outside of Pristina. There's one good highway, it runs from Pristina south to the border with North Macedonia. The rest of the roads suck. Think 2 lane back roads, but not well maintained. There's trash everywhere, and the air quality is brutal, especially close to Pristina.
Its not super easy to get here from the States, you'll have to stop several times, most likely. The Pristina airport is tiny, but nice enough.
Having said that, the country is very beautiful ('ll upload some pics this evening) and the people are very friendly. They love NATO in general, but they particularly love Americans. The food is pretty good, too, and you can get a good meal super cheap. They're on the Euro here, even though they're not in the EU.
It is pretty easy to get to Northern Greece. We're in the southern part of Kosovo (near Ferizaj), and it was about a 4 hour drive back here from Thessaloniki. We drove to Athens, but had an over night stop on the way in Kalambaka. If you drove straight through, it would be about 8 hours. Lots of tolls on that route.
Have not been to Albania, but friends who have been said the beaches are great. Montenegro and Croatia are both pretty close as well. One friend went scuba diving in Croatia and raved about it.
Let me know if you have other specific questions, and I'll be happy to answer.