Possibly he has an avoidant attachment style himself that he has never bothered to work on in his own therapy. I hope he will do it now but surely it will not be a smooth road for him.

Yeah, I can't believe it either. But I also understand how it happens. In the evidence-based world trauma therapist is someone who as learned one or several protocols for treating PTSD, which is a diagnosis for a single traumatic incident - to so called type I trauma. There are also type II and type III trauma, which are often also called CPTSD and relational trauma and attachment trauma etc. These are not official diagnoses and non of these trauma treatment protocols work well in these cases.

So it can very well happen that there is a "trauma therapist" who only knows about the type I trauma, has been educated in using the protocols centered on exposure and cognitive restructuring and who is completely oblivious of the other types of trauma. Thus, this therapist will happily take on patients with trauma (also complex trauma cases), starts applying their expertise on them and is probably quite puzzled and stuck of why their patients don't improve but rather start behaving rather weirdly. Surreal situatation, but as we can see from the picture, it happens and probably quite a lot.