Hi,
Advanced bile duct cancer beyond the stage of surgery has to be treated by palliative surgical interventions like stent placement, chemotherapy (either in the form of IV drugs like Gemcitabine or oral pills like Erlotinib), or radiosurgical procedures (like CyberKnife).
The ideal approach in your fathers case can be determined only after a detailed review of the imaging studies (CT, MRI, PET) done on him.
Treatment at high volume academic centres, or enrolement into a clinical trial, are recommended in your fathers case.
All the Best, and God Bless!