supervision. >> yes. >> you're the medical director. >> reporter: dr. oliver is in fact a very busy doctor. he runs a private practice, has been medical director at dozens of rehab clinics, and also has found time to appear on tv shows. >> 200-degree environment you would only survive just a few minutes. >> reporter: including as a frequent guest on cnn's sister network hln as a medical expert for nancy grace. how he handles all this while overseeing the drug rehab of thousands of california drug medi-c medi-cal recipients is easy he explains. he doesn't see most of the people he oversees who are clients not patients he explains. he admits he wouldn't even know if they are real or as fraud investigators call them, ghost patients. >> you're helping these clinics bill the state for ghost clients. >> well, i don't know that they're ghost clients. >> exactly. so what is your point?