I am dealing with the PTSD. One thing that I found that seemed to be of benefit to me was having the braces. I got the braces about a year before I was involved in an accident that triggered the PTSD. I explained how I felt about the braces seeming to help me. He was willing to work with me on that. I did ask him if he would be willing to make me a set of "fake" braces for when I was ready to get my braces off. I talked with him during my last appointment, and he said that he will use my brackets on a set of Essix retainers to make them.
As for having an "interest" in braces, that is what he does for a living. There would have to be some reason he went to school for that
Everyone has a reason for the job they choose. I think that most orthodontists would be willing to work with us if there was a financial benefit to them. They have expenses for everything they do. In my case, he is making a retainer for me at the end of my treatment anyway. The additional cost is in cementing the brackets onto the retainer. Costs: cement = has lots in stock; labour = maybe an hour; archwire = not much, could use the old one; ligatures = next to nothing.
Braceface2015