Echoing others, this is very real. I had a girlfriend who did this a few times when we were together for a couple of years, although she never was as bad as this, she for whatever reasons (being brought up early by a couple of loving grandparents?) trusted me. The "parental" role thing is pretty much how it always started, and it ended in exactly the same way, after going to sleep she'd wake up normally and not remember any of it. She did always regress to a previous point in her life, at least at one time associated with a very stressful past event. No drug of any sort associated with it, and I suppose it's good it only happened when at home. There was no obvious trigger.