My Husband Has Developed A Cough After Eating And At

My husband has developed a cough after eating and at night. He has been to his primary and he referred him to cardiology and a gasteri dr..they did tests and found nothing . The only thing that helps (at night) is Cloraseptick(sp) . They only said he may have reflux. He has another appt with his primary feb 18th.
Any ideas? His coughing is to the point of gagging.
Thanks, Mary Hada