Imposter syndrome isn't a literal mental illness. (From that he what I understand) It's just more of a way to describe a certain mindset, like the term eighth grader syndrome. Does Dobson think it's an illness, or did he just mention having it? Regardless, since imposter syndrome means unjustifiably feeling like you're a fraud, Dobson can't have it, because he really is one.
He seemed to imply it was an illness. Take a look: https://hypocrisyofandrewdobson.tumblr.com/post/173753598817/ptsd-from-something-most-would-consider-an










