What is the life expectancy of someone with COPD whose lungs are too damaged for lung reduction surgery?

Varies... There are many variables so it is difficult to predict. The most important thing for you to do to slow the disease's progression is to stop smoking and avoid second hand smoke as much as possible. If your oxygen level is low enough, use oxygen which will also slow disease progression. Other treatments are available to control symptoms.
Difficult. This is a very hard question to answer; survival predictions in COPD have been difficult to confirm in study. One of the most widely used is called the "bode" index which is based on body mass, fev1, six minute walk (a measure of exercise distance) and a dyspnea/shortness of breath score called mrc. There are calculators online to help quickly do this assessment.