The term "liver function tests" can be misleading, because not all of these tests actually measure liver function. Many so called "liver function tests" only measure enzymes that liver cells release in response to damage or disease but they do not measure how well the liver is functioning. Tests, such as albumin and bilirubin, do measure how well the liver is functioning.
It is not uncommon for "liver function tests" to be within norms until the liver has severely damaged.
Only a liver biopsy can assess the nature and severity of liver diseases.
Excessive fatigue & malaise can be a symptoms of advanced liver disease. Your mother's condition should be followed up on. That a person can no longer work is a indication of a serious medical condition. Be it physical or mental.
As long as your mother chooses to drink she has an increased risk of developing many medical conditions. Perhaps a diagnosis of liver disease may be the reality check that she needs to stop her drinking?
Good luck.
Hectorsf
It is not uncommon for the liver to be enlarged in alcoholics or if cirrhosis is present.
When the liver becomes damaged enough it can stop producing high enzymes because there is not viable liver left to be damaged. Another common liver manifestation in alcoholics is fatty liver also known as alcoholic steatosis and ultrasonography reveals a "bright" liver with increased echogenicity.
Trinity