I worked in mental health for many years before changing over to pain management about 7 years ago. The guideline has always been, if the treatment is focused on the benefit of one person, it is individual therapy, no matter how many people are in the room. If the treatment is focused on the benefit of the family unit as a whole, then it is family therapy. This is particularly true for children, as they tend to have more therapy with a parent in the room than other people (adults) would. The APA states, "with [individual] psychotherapy, the focus of the service delivered is on the individual patient.... With family codes, the focus is on the family dynamics or interactions."
Reading the definition of PCIT, I would say individual therapy.
Also read the definition of the add-on complexity code, 90785, as that may apply here as well for individual therapy. You cannot bill 90785 with family therapy.