Causes for such symptoms are gastritis,gastroparesis(delayed gastric emptying,a disorder in which the
stomach takes too long to
empty its contents),gastric outlet obstruction,heartburns due to acid reflux(GERD),irritable bowel syndrome,diabetes,hyperthyroidism ,cushing’s disease and rarely GI esp stomach tumors.
Try raising the head of his bed about four inches with blocks. It also might help to avoid eating or drinking for two hours before he lies down.