My Father-in-law Is 89. He Had Colon/ Rectal Cancer 4

My father-in-law is 89. He had colon/ rectal cancer 4 years ago. His bowels have been lose ever since the surgery. He is getting worse, complains of lower back pain and bowel leakage even through out the night. He has to wear depends. He is now wondering if he should undergo a colostomy. He is very weak. Please advise
He also has COPD