My Brother Has Pancreatic Cancer And Is Receiving Chemotherapy. He

My brother has pancreatic cancer and is receiving chemotherapy. He is stage 4, advanced stage w/ mets to liver, lung. He has used CBD oil between his oxycodone for pain. The CBD oil does not seem to be as effective. Also, he's having more nausea & vomiting, lack of appetite.. I know he meets the criteria for medical marijuana, but will it be effective?