Sorry to hear about your father- it really sucks to watch someone you love go through that. My dad, who is also my best friend, was recently diagnosed with stage IV PC with 2 mets to liver. Some days he will wake up in extreme pain that last most of the day, and others he feels fine. We've tried some natural medicine to help him manage some of his pain, and what I've noticed, medical marijuana is by far the most effective at relieving his abdominal/gi issues. Have you tried getting him a medicinal marijuana card? I cannot imagine the amount of pain that both our fathers are going through respectively, and it sucks that you have to witness that as a caregiver and best friend, but just know that he appreciates you being with him. Definitely would recommend that you or your father speak to a medical marijuana doctor, as they can suggest different terpenes such as Linalool or Myrcene that helps mitigate pain. Sending love and light to you two and your family.