is this herbal remedy being done instead of other treatment?
the best chance for your mother's survival is not herbal treatments. her doctor should be able to explain this to her better than you can, but something simple you can say to her that might help her to understand why herbal treatments are not likely to be effective follows: her cancer will affect her bodies ability to absorb nutrients. it is very unlikely that she will be able to process the herbal remedies she is given and furthermore may actually stress her liver and pancreatic function leading to negative effect.
if she is interested in alternative treatments there may be clinical trials available to her that study the effects of hemocyanin (specifically Keyhole Limpet Hemocyanin) on antibody-dependent cell cytotoxicity. basically doctors try and create cancer vaccines using hemocyanin cells from another organism (the keyhole limpet) and cancer cells from a patient to train the immune system to fight cancer in the body of that patient.
see if your mother's doctors know of any such ONGOING trials. if they really have caught this early, she may be a good candidate for such treatment.
i am not interested in giving you or your mother false hope, but this treatment is a real alternative (unlike herbal medicine) that has shown promising results.