Suggest Treatment For Chronic Nausea And Abnormal Weight Loss

My wife (83 years old) has had nausea 24/7 for the past 12 months. Never has vomited any time. Has had gasoscopy & colonoscopy {1x8mm polyp removed }. Helicobacter x 2 treatments of antibiotics .Breath test clear. MRI of stomach (all clear). Ultra sound of ovaries, etc (all clear} weight loss 50Kg to 44.5KG. 5 prescriptions for CTZ medications. None made any difference. Thanks for your opinion Ray Greig Australia