Symptoms not good. The same process!

Hello Doctor, This is Shobhit Sahu from Jamshedpur and my father sushil Kumar Sahu was facing loss of appetite, less Haemoglobin,(came down to 6.3 but after blood transfusion it is 8.2 now), weight loss, weakness, complains of back pain. But he never complained for blood in stool which i doubt. His colonoscopy was performed yesterday but doctor could not obtain biopsy line  due to denate in anal line. Doctor is recommending an anesthetic biopsy. I have attached all the reports. He is a diabetic patient as well and diabetes has been fluctuating for some time now. 7 years ago my grand mom underwent a surgery as i suppose she had a cancer in the rectum and her intestines had to be removed. A permanent stoma has been created for her and the normal process of passing stool through anus has been stopped. Initial opinion of the doctor is to create a permanent stoma for my father as well, similar to what they did for my grand mom. I do not want my father to undergo the same process