There are elements of it that seem to resonate with my therapy.

For me, the slide show itself is annoying and was hard to watch because of the voice over. The content wasn't too much different than other IFS and parts work stuff I have read/seen.

I'm not sure how what this slide show talks about and your T becoming strict are related. It almost feels like that would be the opposite of what this is trying to explain, especially around the concept of helping the child part feel seen/heard. I do notice that this method seems strongly focused on being able to engage in and with those adult parts. This would be a problem for me because I don't have good, strong images of healthy and balanced adult parts. This is what I have considered the reparenting element of my therapy. I am learning from my T the nurturing and compassionate elements that my current adult parts are missing.

Has your T explained his distancing and how it relates to this theory? Has he been trained in this theory or is it just a new fad that he's grabbed onto? If he has gone through their training, how long ago and is he getting direct supervision?

Since no one method works completely in silo to other methods and works for all clients, I'd urge you to talk to him about why he now thinks this method would work best for you and so on.

I'm also questioning the strict and distancing behavior you describe, in light of recent emails and misunderstandings around ED. I wonder if he is being reactionary in response to your emails or if there's some residual feelings you have about the interactions that is resulting in you seeing him as being more strict or distant than in the past. Neither or both could be happening.