My father in law has been experiencing episodes lately. He is 60years old, has had bariatric surgery in the past two years. He has had several of these episodes, marked by rapid onset of extreme exhaustion, followed by irregular heart rate, and most recently.. spontaneously falling asleep- with some periods of being able to hear a person talking but unable to respond and very difficult to stir/stimulate. He has been transported by ambulance to the emergency room, followed up with cardiologists and primary care doctor- to no avail. He literally goes unconscious spontaneously. Could be while driving, walking or sitting still. Any thoughts?