my husband is recovering from prostate surgery and bladder tumor removal , the surgery was over a month ago. He has not had control of his bladder since then, and for the last 5 days has diarrhea. it started as brown watery and now is blackish dark green watery fluid, a little thick sometimes. it happens every 10 to 25 minutes. he does take several antibiotics, mostly for ongoing bladder infection. what do you think it could be from. I want him to go to e.r. but he is so weak he cant walk.