Well, most things are context driven, and, since you say your therapist is rather blunt, I think you have to look at the overall tone and contextual framework of your therapy.

At first glance, I was like "WHAT???" at your therapist comments. However, when I thought back to some of the things that my therapist said I was like "WOWSA" without some context that man would probably lose his practice!

Strange, but the thing that I find most inappropriate is him ordering a book for you online without you asking. Maybe he gets the books for free or something. If so, why would he tell you about it and not just give you the book?

So, you've got your gut feeling, and that's hard to ignore. Really hard. Once the notion of predator has entered into the mind, it's hard to root it out.

Rather than a Dear John email, perhaps a pre-Dear John email or phone call?

It could simply state that "an issue has come that is leading me towards termination. Before I make that decision, I want to have a discussion with you about it. I know you said you were booked, but this is quite important to me, let's try to address it sooner rather than later"

The question then becomes, if this guy has an explanation for his actions/words could you ever accept it at face value? What would a good explanation look like? What would it take?