I think it would be a much easier treatment if the patient felt comfortable pursuing his or her goals and could allow themselves to actively work toward their goals and inhibit the behaviors that got in their way. My experience and Control Mastery Theory teaches me that although patients want to get better and lead productive lives, they are often in conflict about pursuing these goals. The conflicts often come about from irrational beliefs about the consequences of these goals. They might act as though they really want to be in a relationship or get a great job but their actions indicate that they are in fact acting in a manner that is counter to their stated goals. I would wonder if they are suffering from a belief that they do not deserve to have what they might desire due to their irrational beliefs associated to the action. In Caroline's case I think that she felt as though she didn't deserve to live - her very life took more than the family could tolerate and her desires for an independent life were a death sentence to her parents. Dr. Edmund suggests that Caroline was very far away from feeling free to limit her contact with her parents. She tells us she noticed that the daily contact was confirming Caroline's worst beliefs- (this was in spite of the fact that her parents were trying to help their daughter get better) punishing Caroline to be different, go to school and get well - and making her feel more suicidal. The parents were very upset about their daughter and had many conflicting theories about the cause of her problems hoping to assuage their guilt and fears that they caused her problems. Jamie chose to intervene in this direct way to try to create a space and place for the patient to gain an understanding of her conflicts.
I think you are right in worrying about a therapist who imposes goals unilaterally risking replicating unhealthy parents. I think the trick to treatment is in making your best guess about how the patient is using you in a particular session (assessing what the test is) responding to the test, and then watching your patients reactions to determine if you were in the right ball park. It is not an exact science by any means and it is an expected part of the process to err and read adjust your responses as you gain a better understanding of your patient's plan and goals. The difference seem to be that we do not think that patients can always tell us what they really want and in fact will often tell us the opposite to see if we do not think they deserve much either.