Hi the clinical picture presented by you suggestive of GERD , Gastro-oesophageal -reflux -disease. The patient gets violent cough due to regurge which comes in throat and induces vomiting too. And a violent cough can cause vomiting if the sphincter ( valve) stopping the stomachs content into oesophagus is week. This can be the reason for vomiting for a year now. This will cause the weight loss. You already have seen so many consultants and the patient must have been really taken care of, but without any benefit. In such patients my first advice is to go for a CT scan of the brain as some lesions in brain can cause this ( just to rule out). There are very small efforts to make to improve patient s condition. First of all take small frequent meals . Never to lie down at least for two hours after food , better to walk around or sit in a reclining position. Thirdly you and your wife have to really find out which of the foods aggravate/ increase the problem and stop them. Your consultants would have definitely given her metclopropamide or domperidone and antacids in proper doses. Lastly thee is something called as psychogenic vomiting if all the causes are ruled out.