Not that I'm saying your friend is definitely wrong, but very depressed people often remember things very differently from the folks around them ...
That was not my "first response," and I did not say that the friend was remembering things wrong. I said that that was one of the possibilities
in that situation.
I attempted to answer the question(s) that the OP asked -- would it have been more helpful to say that, yeah, the doctor was probably an ignorant quack? Problems with memory, concentration, and cognition are known symptoms of depression -- if I had a dime for every time over the years that I had a patient on an inpatient unit comment to me that the doctor didn't see them that day, or something didn't get done that was supposed to, when I knew
personally that the doc had
seen them and whatever is was had
gotten done, I wouldn't have to work any more. I don't think that's being critical of the individual in any way or accusing or blaming them for anything; it's just recognizing the symptoms of the disease.
It is also not at all unusual for teens to recover from a severe depressive episode and go on with their lives successfully. I, too, am glad that is the friend's experience in this case