What Causes Severe Headaches While Suffering From Disc Degeneration?

My husband has problems with his neck for years now and is diagnosed with disc degeneration and bulging. He gets terrible headaches from doing any kind of work. He cannot work now for ten years. The specilist surgeons will not operate because it is so severe it would be dangerous. They will only weld them together if he wants. Today, he woke up and was not well again as usual but something was worse and he called 911... when the ambulance got there he could not remember why he called. They took him to the hospital and on the way he called our daughter to tell her with his cell phone and still does not remember doing that. They did a CT scan of brain and blood work and found nothing. Sent him home. He still cannot remember that period of time.