Hi Ben,
Cholangiocarcinoma is not considered a disease that is inherited. Below is a site that explains this. It does say that family members may have an increased risk. I have read anecdotally about one or two cases where two persons in the same family had CCA, but such cases seem very rare.
I am not a science person, but it seems to me that in a case where two family members share an illness, the question is out there whether there is a genetic factor or something else that is shared, such as an environmental factor, for example, the CCA cases related to raw fish consumption in Asia.
https://ghr.nlm.nih.gov/condition/cholangiocarcinoma#inheritance
Regards, Mary