My Friend Is Between 45 And 50 Years Old. He

my friend is between 45 and 50 years old. He has has diarhea, nausea( but not vomiting), he has nasty burps and gas. the diarhea hits about midnight and then doesn't let up for several hours. He takes imodium and is fine until the imodum wears off. He also gets severe hot flashes when the symptoms resume.