Hello there, Thank you for your question. I am Dr Asanghanwa Carlson. Going through your question, I see two distinctive but linked problems which are a stage four lung cancer and secondly a pneumonia which is a chest infection. Stage four cancer is itself a serious medical condition requiring intensive medical care as this mean the lung cancer has spread to other parts of the body and little or nothing can be done to treat the cancer in itself. In such circumstances the right kind of treatment to be administered is supportive therapy where only the basic minimum is administered to the patient. Having lung cancer predisposes him to having repeated chest infections as germs the body s defense mechanisms are weakened by the presence of the cancer and also some tumours might compress his airways making it difficult for him to expel inhaled germs. Having a stage IV lung tumour and a pneumonia is therefore a serious medical condition requiring intensive care management for the infection. Pneumonia on stage four lung cancer is not the last stage before death but it can seriously reduce chances of survival if it is not appropriately managed. I would just advice you visit him when you have time and comfort him while he receives help for his condition. Good luck