All Dick is doing is conveying an a series of experiences he had, and in life all we can be truly sure of is what we experience as an individual. For Phil, these things happened, and were important enough to change his life and build a philosophy around.
Who is to say if he was mad, insane, crazy, or paranoid?
The Exegesis is simply a personal work of a man trying to figure things out. Also, these things that happened to him and the things that he experienced shaped his fiction more than anything else. To understand Phil more is to understand more the worlds and characters that he created. And after all, his fiction became more auto-biographical as time went on, so is there really a difference between the two?
It is a great treat to be able to look into Phil's mind in this way.