Everyone is different when it comes to what they can and cannot eat after this type of surgery. My son had his entire colon removed and eats just about anything he wants. He has a few "trigger" foods that he avoids. It's really trial and error as to what will affect each individual. He needs plenty of fiber, needs to stay well hydrated, and eat yogurt enriched with probiotics. Until his system gets back to normal, dehydration can happen very easily. Bananas, orange juice, and Gatorade are good for replenishing electrolytes due to dehydration. He needs to take one food at a time away and see if his BM's improve, if not then add that back and try another. It is truly trial and error with his diet. Bulk building foods are normally best. Also, I would contact his doctor about this and see if he is able to take an anti-diarrhea medication to help. My son took Immodium in the beginning for his, prescribed by his doctor. Hope this helps, and your husband can start to feel normal again. Take care!
Look for posts by Morecambe on diet following colon surgery. Even though this person has part of the colon left, he will experience changes in bowel composition. The large bowel has a function of reabsorbing a large proportion of the water that is in our system. When a portion or the whole of the colon is removed, a lot of that water will be 'lost' to the outside and the fecal material will be looser than previously found. Changes in diet can help that.