Cannabis for Cholangiocarcinoma – Any Suggestions?

I am looking to potentially give my father Cannabis to help primarily with pain and comfort management.  Right now he is struggling also with bowel movements as cancer has spread into his abdomen and frequent bloating. I know barely anything about Cannabis so I am wondering if anyone has any recommendation on how to go about this.  Any particular strains that’ll be good for pain, sleep, bowel movement or even cholangiocarcinoma specifically?  Any guidence would be much appreciated.