He has multiple problems that need to be streesed. He is only 54 and needs to have a good and healthy life style. Involve him. 1. Nicotine dependence. Consult an expert. 2. Obesity: diet, walk/exercise. If no response in 6 months consider Endoscopic balloon  placement in stomach or bariatric surgery is an option. Consult dietician, bariatric surgeon, Gastroenterology. 3. For arthritis and back ache : physiotherapy. 4  Gastritis: see a Gastroenterologist and get an endoscopy done, then proceed.

Hello All his symptoms may not be related to gastritis like knee pain. First of all he has to stop smoking. It is the single most important co-factor. Other life style changes include - regular meal pattern, small frequent eating, regular walking. high intake of vegetables and fruits. Definitely there is a good treatment available for gastritis including cure.