Hi. Thanks for your query. Noted the history about your Mother and understood your concerns. Since there is already an autoimmune disease like Polyarticular rheumatica, inflamed stomach and diverticulitis the reason for colostomy is usually for rest to the colon as there may be additional problems in colon. So go for it. In many cases the colon needs to be resected too. Please follow the guidelines of a Rheumatologist and Gastroenterologist for her to get a proper management and better life as all these conditions are debilitating and carry a high risk to the life, recurrent infections and so on. Follow the diet chart as given strictly. Identify the foods and beverages instigating or enhancing the problems and stop these altogether irrespective of any opinion.