Rectal cancer (adeno carcinoma) - stage

My dad has rectal cancer stage 4, he is undergoing chemotherapy, 7 chemo done 5 still on the way the tumour is out of his anal a few centimeter due to which there was infection on the tumour due to passing of stool due to which from 2-3 month he is suffering from tremendous pain ,he cant sit properly, he had to sleep on one side, blood is coming from his stool sometime and unable to control discharge of stool, he dont even know when the stool get pass from his body, my father surgical oncologist said operation can be done so that infection wont happen and cause of pain might be less, we also consult other surgical oncologist about they said operation dont reduce cancer but it will prevent from happening infection, so my question is does operation will help to reduce my father pain even half of the pain, the blood discharge coming from his stool. Please help me he is my father i know i cant save him but atleast whatsoever time is left for him he should not have that pain.