Dealing with a fistula

I'm new here and hoping to find someone who has had a similar experience and possibly some suggestions. My 54 year old husband was diagnosed with stage IV colon cancer in early August. It's very advanced. He had a colonstomy and exploratory surgery with biopsies right away. Of course, he's had CAT & PET scans. There is a large mass that essentially has filled his pevis like concrete (surgeon's description) and endangered all the internal organs there, so surgery to remove it is not an option. The cancer has spread to his liver and prostate and there is bladder involvement. He has a fistula, or hole between colon and bladder. This bladder/colon opening is really making his life difficult and so far, the doctors haven't been able to offer any help or even the hope for relief. I searched the forum and didn't find anything along the lines of what I was looking for (perhaps I didn't use the right key words), so I hope this isn't a redundant post.

I'm sorry, but the following will be fairly graphic and not pleasant :-(

At this point (today) his UTI is under control, but that hasn't been easy. The poor man is plagued by the need to urinate ALL THE TIME. Seriously, at least every hour. It wakes him up out of a deep sleep and if he changes position, he has to go. If he even thinks about it, he has to go - and once he has to go, he has to go immediately. He always keeps a urinal on hand at home. Yesterday, we went to oncology to have his chemo pump removed. He went to the bathroom before we left, we drove ten minutes, I dropped him at the door, went to park the car and found him on the sidewalk frustrated that he hadn't been able to get inside before having to go again. Well, that's what Depends are for... Ten minutes into being hooked up to IV fluids, he had to go again. We barely made it to the restroom. He went once more before he was finished with fluids. We went down for a quick bite to eat in the cafeteria. I ran ahead to get the car as we left and once again, found him mortified on the sidewalk. That was 4 times in 2 hours!

Now, I know that sounds bad enough, but it's not really the worst of it. The worst is that there is mucous caused by the cancer that 'wants' to be expelled through his rectum. The ostomy is doing its job, so this pink slime is all there is. Every time he has to urinate, he also has a strong need, actually a compulsion that he can't control, to strain and evacuate this pink slime. So, imagine him straining against his will while he's standing on the sidewalk. I'm worried on so many levels. He's not getting any rest. He won't leave the house. He's ashamed and worn down to the point where he doesn't wear pants at home - just Depends. Keeping him hydrated takes a lot of work.... The fistula cannot be repaired by surgery because of its location and how fragile the tissue is. The urologist doesn't have any ideas. The oncologist prescribed an anti-diarrhea medication and ID has prescribed an anti-spasmotic for the bladder. We'va also tried muscle relaxers. 

Has anyone out there dealt with anything like this or does anyone have any ideas?