What Causes Sudden Chills Followed By Mucus Drainage Into The Abdomen?

My husband is 69 and gets chills so bad he can hardly move. He will grab a blanket and we live in Tucson, AZ. This is the first symptom of a problem he has had going on 9 years that no one has been able to diagnose. Next he will wake up and instantly start having thick, massive mucus drainage down his throat. Some is in his nose but mostly it drains into his stomach. He gags because it is so thick and brings it back up. After 12 hours almost non-stop. Evenutally the mucus in gone but liquid and bile come up. He is then exhausted and sleeps for at least 12 hours. He can t eat until day 3 and then it is only chicken broth and noodle soup in very small quantities. This can last from 3-5 days. He has seen ENT s, allergists, been to the Mayo Clinic, hospitalized 3 times. No one can do anything for him. He is now seeing a Naturopath and undergoing chelation every 3 weeks. It seems to be helping but he just recently had another bout. I m wondering what regulates the body temperature since this is always the first symptom?