In any case, he shouldn't be content with simple analgesia. He should be examined by a doctor who will take his symptoms more seriously. In addition, he needs an MRI scan, perhaps followed by a myelogram which is a special type of X-ray that will show where and to what extent the nerve is being pinched. Ask your father's primary care physician for a referral. The body becomes primed for crisis, and Nature makes sure that the dreamer wakes up in order to cope with stress in a realistic way.
Awakening is the method by which the brain shuts off the continuing barrage of threatening stimuli.
In this way, sudden awakening can be viewed as a normal adaptive mechanism to avoid unwanted or unusually scary thoughts, much as our brains use the startle response when we are awake. Be sure to mention the title.