Suggest Treatment For Cluster Headache And Tingling Sensation In The Feet

My husband (50) recently visited the ER with cluster headaches twice. After blood results and CT scans with and without contract came back clear. Blood results were fine as well. As the weeks progressed (on week 4 now) the headaches subsided then he came down with nasty lesions in his throat. He was unable to speak or eat. He then broke out in a rash on his foot. He was tested for strep, and shingles (negative) He can sleep up to 18 hours a day. He is constantly fatigued. Just getting up is torture. His lesions have gone away, now he has a persistent cough. He has lost 20 lbs over the last four weeks. He has been on steroids, antibiotics, nothing seems to help and the doctors cannot pinpoint what this is. He now has some tingling in his feet and hands and head. He has been back and forth to the doctors at least 5 timed in addition to the 2 ER visits. There is nothing in the chest X-ray they did today either. They also tested him for Lyme (today) and Mono. Any ideas?????