Thanks for pointing me in this direction of this thread. And I think you are right. This has all the signs of the onset of Schizophrenia, to me. Disclaimer- I worked as an Mental Health Professional and was the Associate Director of community home programs for 16 years. I have a Masters Degree in Counseling, along with my certification, but we will consider this not a professional assessment (as I am not verified). We will consider it my life experience.
Few things--- (I will apologize in advance. After working directly with the most chronically treated mental health adults for 16 years, I tend to explain through examples and stories. Never giving enough info to break confidentiality, though)
The fight- did anyone ever say they saw it? Or did he just report this to his friends after he disappeared. I am doubting this ever happened. I once had a "client" (we don't really call them that, but we will say that for ease) who I had brought out of town for Special Olympics (dual diagnosis). We finished eating at a restaurant and she said she needed to go back in to go to the restroom. We all waited outside, but I watched her through the window. I WATCHED her through the window. She reached the bathroom, turned around and ran out the restaurant screaming about how some b**** just accused her of sleeping with her husband and punched her. She then proceeded to try to punch me. She was very convincing! People were not sure if it actually happened. But, it did not. It was part of her delusions. No woman even spoke to her, much less punched her. I was watching. I say all of that because it is highly likely he believed this himself, but it didn't happen. He could have also hit himself, put something in his ear, anything that caused damage. If a person is having auditory hallucinations, it would not be uncommon for them to stick something in their ear to try to make it stop. Unless there is corroboration that the fight actually existed, I'm not going to 100% bank on it yet.
As for the airport- I immediately noticed the lady he walks past. If you notice, it almost looks like he says something (possibly non-sensical) and she points the way. It is the same time the guy in the blue turns around and looks. I am going to bet if they talk to blue guy, he will report Lars either speaking loudly or saying things that seemed bizarre, which is why he was looking over his shoulder. Blue guy was looking out for his own safety, not looking to harm someone else, I will guess.
The thing that seems consistent throughout the days/ weeks leading up to this event is several people saying he was paranoid, acting strangely, not acting quite like himself, etc. This is common when someone is in the first stages of discovering it is Schizophrenia. People around you believe you! So, instead of realizing it is delusions and paranoia, people try to help keep a person away from the perceived harm. A big clue is him asking his mom about the number and letters on the pills. In my experience, most delusions surround government, God/ satan, someone (doctor, etc) trying to access control of them, tv and microwaves trying to control thoughts. To be paranoid about the pills would fit right in. They were very likely antibiotics that we all take and nothing more.
He had "someone" after him for a long time. This is likely perceived, not real. He left his friends and not only was he jumped, but there were groups of Russians and Bulgarians (Dont remember the specific groups) that did it. And no one saw. Then, a doctor wont let him leave. Then there are 4 guys following him at the hotel. Then, the hotel people cant be trusted and credit cards need to be canceled. Then, the doctor (who is obviously working with the pharmacist) gave him pills that were tainted. Then, the doctor at the airport wouldnt let him leave. And the airport personnel was terrifying and he needed to run from him..... do you see what I am getting at?
To me, Schizophrenia is the scariest thing that can happen to a person. Most of my "clients" were intelligent and had lived their lives like every one of us. Until they didn't. The fateful day that Schizophrenia took center stage. Most of them related the onset to a single time of drug usage. A very specific time. The best way i describe Schizophrenia to people is to imagine your dream state and your awake state meshing together. You can never know what things really exist or what things are just part of the dream state, leaking through into your reality. There is also usually some parts that are true. I had one of my guys tell me there were human bones in the garbage can upstairs. I went to investigate (with gloves on, of course, because you never know!) and it was an apple core. When he glanced into that garbage, the apple core took the shape of a finger bone. All of us can understand how something like this could happen in a dream. It is sadly the reality that they often live, not knowing if threats are real or perceived. And Schizophrenia can be very well controlled on meds. But, that takes a person knowing what is happening and receiving ongoing treatment.
My guess is that he all of a sudden thought his sweet mama would be in danger or possibly was part of the plot against him. He is probably living among the many other untreated mental health adults living as homeless. I hope they find him. Someone asked where the trucker brought him. That is a GOOOOD question. And an important lead to follow. I feel like he can be found, but it will take lots of people sending photos of homeless from all over the place. I always think about how many of our "missing" are probably right under our noses and ignored as people on the streets. I hope he is found and helped real soon.
I'm available for any translating needed 
