I'd hate to indirectly give you a pressure but if you decide to continue this plot, please let me know! I love this sort of story dealing with characters' psychological effect from their real life experience! Indeed, the former Yugoslavian countries are truly fascinating. It's sad that a lot of people focus mostly about the wars in the 90's when there are so many unique and pleasant topics to learn about these countries. For example, recently it's such a real pleasure that Konjic woodcarving was acknowledged by UNESCO.
Concerning the Yugoslav Wars, I have an OC who's a Croat-Bosniak whose life has been directly affected by the war. His hometown was in the middle of conflicted area between ethnic Croats(his father's side) and Bosniaks(his mother's side) so it left him a really bad trauma. Currently I'm considering to revise him but I'm still not quite sure if I want to discard his psychological troubles (he tends to 'snap' and becomes almost mindlessly violent when he encounters discrimination and hatred based on ethnicities, even when it doesn't directly happen to himself, despite being a timid, peaceful person most of the time). On one hand I use his psychological troubles to present how the PTSD condition is a common problem among people who suffered from the war, but at the same time I feel I'm portraying people from this region in an undesirable light.
They're really interesting countries! And I get what you mean - you rarely see things set there that don't focus on the wars (or partisan activity in WWII, I guess). I wanted to try to focus on a new generation, and how the past affects them. The fact that Tarik is even studying Peace and Conflict studies is as a result of the siege, I gues.
I don't think he sounds undesirable; I think it sounds normal for someone with PTSD to lose control when they enconter prejudice after they'd witnessed a genocide. Obviously, whether the character is a good portrayal of someone from the area also hinges on how three-dimensional they are, and what they're like when they're not having an episode.