What is a good diet after colon surgery? Are probiotics good?

My husband had almost his entire colon (5' of it) removed 8 months ago after diagnosis of Stage 3 colon cancer. There has been a problem with diarrhea ever since: 5 - 8 loose stools each day and the occasional accident when he does not make it to the "reading room" in time. Any suggestions for diet to (1) keep hydrated enough when there is no large bowel to absorb water (important since he also has only one kidney and diagnosis of moderate kidney disease) and (2) have firmer stools rather than chronic diarrhea. Dietitian has recommended that he drink lots of water for hydration and physician said he can take 8 tabs of Immodium daily plus Metamucil and eat lots of water-absorbing fibre (like bran buds instead of bran flakes) to reduce diarrhea. Increasing Immodium and Metamucil has helped a bit but still suffers from diarrhea on a daily basis. Any ideas??? Suggestions about foods he should avoid or foods he should eat?