It might be helpful for the two of you to go to the surgeon together and find out what the surgeon said about the problem and potential solutions. It’s likely the physician outlined some of these things for your brother. Many people leave the doctor’s office without remembering much of what was said.
Sometimes it’s true that patients are considered medically unfit for surgery. In your brother’s case, you mentioned several risk factors (diabetes, smoking, overweight) that could put him at too great a risk for surgery. That’s when conservative (nonoperative) care may be recommended.
For patients who are medically unable to have surgery and for those who don’t want surgery, physical therapy has been shown effective as a nonoperative approach to treatment. The therapist shows the patient ways to move that will reduce the stress and pressure on shoulder structures. At the same time, a strengthening program is used to strengthen the muscles that still work normally in order to restore as much normal shoulder function as possible. Steroid injections may be used to help with pain control and improve motion during therapy.
Smoking cessation, increasing physical activity, and weight loss are not out of reach even for the most out-of-shape people. By working on improving overall health, your brother may find it possible to have surgery later if conservative care fails to provide him with the pain relief and improved function needed for daily activities. Your support could be an important part of his future success with such a program.