Still, "informed consent" implies information is given by the doctor that is consented to by the person being treated. Like, if you have this operation you may die. What is the parallel here?

The therapist does not function as a human lie-detector test or machine. The therapist creates a safe space where perhaps one day the patient may be able to tell the truth.

My parents taught me to lie to them. Thereafter, even when i told the truth, they thought i was lying. Sometimes i was, but mostly i wasnt. But they started it when they promised they wouldnt punish me if only i would tell the truth, then laughed and said it was a trick to get me to confess and punished me. The trick part really hurt. Why does your liar lie?