If someone has de compensating cirrhosis, what is the average lifespan if the person does not get a liver transplant?

Depends: If ascites and edema, elevated bilirubin and especially upper gastrointestinal bleeding occur, the average lifespan is less than a year. However, alcoholic cirrhosis can be treated with steroids in some cases, and this may prolong life. There are other things to reduce bleeding, and decrease edema etc., treat other symptoms (itching) that may improve lifespan and quality of life some. Stop alcohol.