We have seen other cases where a person goes missing after a crash. Sometimes the remains are not found for a year or more - and may even be close to the initial crash. Sometimes the remains have not been found.
I think his father is so extremely loyal, determined, and a wonderful parent. I do wish that he would admit that his son may have been having mental health issues at the time he disappeared. Being honest about the situation is important. My son is 21 and had a mental health break. If you talked to him briefly, you would think he was normal and everything is fine. But, if you spent a little more time with him, you could see that things just didn't connect in this thought patterns. When everything came to a head, he was pulled over by police and put in jail because of reckless driving (basically). No drugs or alcohol in the car. But, when he was "evaluated" by a jail psychologist, she said he was "just a drug user/abuser". However, when we were finally able to get him in to an inpatient facility, he has either bi-polar or schizoaffective disorder. Once he was medicated for that, his thought patterns and verbal responses make a lot more sense. I can tell you that if he had crashed his vehicle and lived, he would have likely wandered off in an unknown direction.
Talking about Daniel, this is Arizona in the middle of the summer, in the desert. Very hot! Heat, mental health issues, confusion, dehydration... Add all of these things together, and I fear that he may still be out there but has not yet been found. I honestly think this was a storm that came together. IMVHO, I think Daniel is out there and there is no foul play. I really, really hope they find him for his family's sake. I just don't see a dark side to this story, just a very, very sad story!