It has been seen in many cases that Gall stones
are associated with Cancer. At stage 4, we must treat her according to her symptoms. Our idea is to make her as comfortable as possible. If she has pain due to Stone, that also can be removed by laproscopic surgery. It all depends on her actual extent of disease, and the facilities available in your vicinity. There are some clinical trials also going on in developed countries for treatment of Advanced cases of gall bladder Cancer
as a radiotherapeutic modalities. Robotic surgeries also possible in selected cases.
May be if you can provide more details, we would be able to give you precise answers.