Talk to Cancer Surgeon on Oral Cancer Stage 4

oral cancer stage 4.he is 56 years old and he is going through stage 4 oral cancer.we have his biopsy and ct scan from where we got to know his stage.we went to shakt khanam lhr but they dont take stage 4 aged patients.now we are going karachi.can you please tell what are the chances of survival through mouth surgery or if we go cyberknife(jinnah hospital) he is diabetic too.is there any complctns in surgery in stage 4 at this age being diabetic.and if we dont do any treatment what can happen..?