No, Cassiebabe, liver disease is not always caused by alcohol. Liver disease can also be caused by various infections, injuries and trauma, obstructions such as gallstones or tumors, immune system disease or weakness, and overuse of drugs (including prescription drugs), and environmental toxins - such as those in air pollution, house and garden chemicals, and many of the preservatives and additives of food. Liver disease can also be genetic.
Cirrhosis (or sclerosis) is thickened or scar tissue resulting from liver damage, which prevents the liver from normal function.
While alcohol is a common cause of liver disease in the U.S., it is probably more because so many are heavy drinkers - not because alcohol alone is the cause of liver disease.
Treatment for liver disease has made good advances. I hope your friend does well!
Those who contemplate the beauty of the earth find reserves of strength that will endure as long as life lasts.
~ Rachel Carson