With only cursory info, I at first thought he may have been murdered and the accident and walking off was done by someone else posing as him to throw off the case. A murder investigation is a bit more challenging with no body and a witness seeing supposed person walking off. If that were the case, then the murder likely would have been committed by someone close enough to be a suspect. Also, the murder conspiracy likely would have been premeditated and carefully planned, though not necessarily. A premeditated murder would likely be committed to eliminate a witness to organized crime, possibly involving corrupt law enforcement who would be able with their insight, to concoct an effective plan to throw other law enforcement off the trail. I also considered the possibility that the parents could have been involved in his murder, perhaps to protect family secrets. I would carefully crosscheck all their assertions and statements with phone records tied to the cell tower location data. I would check for a change in pattern in the young man's communications leading up to his disappearance; he could have been murdered some time before. In short, any effort to throw law enforcement off the trail would mean guilty parties aren't far removed. What really got me thinking this way was the failure of search parties and dogs to track him. I'm not privy to how the search with dogs actually went, but I had to wonder if the failure was because it wasn't him that walked away but someone posing as him who deliberately caused an accident triggering a witness to his supposed disappearance. Was the dog search done using an object with his scent???? Was the work phone a deliberate plant???
Here is what I now lean toward:
The video of the parents makes them seem genuine, though ten grand does seem a bit paltry for a seemingly middle class family to offer for their son. No disrespect to the parents, I don't know their financial situation. No disrespect to the young man, but he appears a bit disheveled and unshaven (likely un-showered) in the pics. Disheveled may be a bit strong, but for a 24 year old, he doesn't seem groomed for purposes of attracting the opposite, or even the same sex. Please, I absolutely don't want to insult him! I'm thinking he may be a bit socially awkward and not finding the fulfillment a young man should have. This may be related to mental issues. Looking at his pics, I just get an impression from his facial expressions something may not be right. It could be my own bias; I can't really put a finger on my impression, but I'll call it as I see it. I suspect he's had some issues with mental health. I also suspect he may have become delusional and paranoid. That could have played a role in why he got into the accident. It also could explain leaving his cellphone in the car. In a confused and paranoid state of mind, he may not have discovered he had his work phone on him right away, and ditched it to avoid being tracked upon finding it on his person. In a paranoid state of mind, he might be careful to avoid businesses and places he would expect there to be cameras. I'd consider searching places a paranoid person would hole up to avoid detection. Abandoned buildings, heated but vacant areas of businesses, ensconced in the back storage area of a retail store, the labyrinth of a hospital, or similar areas may be worth noting. Despite his possible best efforts, he has surely been captured on multiple cameras if he has wondered about on foot. If paranoid, he could have taken steps to change his appearance and clothes. He must have become very hungry so I would get the word out with his picture to food establishments. Hopefully the police are interviewing his roommates and everyone close to him for clues about his personality, mental state, and even the possibility of foul play. I also have to wonder if he got introduced to psychedelics or other drugs, in Chicago or elsewhere, that may have catalyzed psychosis.
Well, those are my thoughts devoid of any other evidence. I'm praying for him and his family.