At first glance, it seems inappropriate. But I think most boundaries depend on the patient and therapist (I just posted an article about this). My former T went to a patient's wedding before. He's told me some other things too, but I don't want to post all the details here.

I think it could be reasonable with a patient with no childhood issues and a certain type of therapist. One of my first therapists long ago was more like a friend to me. Back then, I didn't know about boundaries, but it would have seemed perfectly normal for me to go to lunch with her, for example.

We all don't know the whole story, as everyone here must realize, but do you think your friend might be exaggerating in some way? Maybe her mind created this fantasy as a way to deal with the perceived rejection she might feel if her therapist does not allow outside contact? Just a thought that crossed my mind...