Your mother can do blood for Alkaline Phosphatase
,bilirubin , and gamma glutamyl trandspeptidase.These are increased in liver metastasis.
She can also do blood for haemoglobin
and albumin which are decreased in this condition.
CT scan of upper abdomen with contrast needs to be done.
If liver space occupying lesions are found then ultrasound guided FNAC or biopsy is suggested to prove liver metastasis that is spread from primary breast cancer
Clinically patients develop jaundice, ascitis, hepatomegaly
, tenderness, cachexia and some times fever.
Regards and Take care