Attachment was a psychoanalytic concept, but has now been accepted as science. T's are required to keep up with the field. They have to take classes or workshops to keep up. It's required to keep their licenses. So if a T has not accepted that attachment is part of therapy, then there is a problem.

This may be straying off topic from the original poster's questions. Not sure. Just don't think that what has happened is ethical or legal. Also don't think it is muddy.

Client abandonment is not OK. Doesn't matter if there are different points of view. If the client is in distress from the T's behavior, the client has a right to say something about it.

There are studies that say that the client, not the T, has a better sense of what works, what doesn't, and what the T is doing that is wrong. The client may not have enough information, but they still are more sensitive generally and are often not wrong.