Hi Tania10,
That's...unbelievable heartbreaking...i'll get right to the recommendations I think.
I am not sure what state you are currently in but the Australian Government Department of Health regulates therapeutic medicines containing cannabis through the Therapeutic Goods Administration. So apparently in Queensland all doctors can prescribe S4 cannabidiol (CBD) without Government approval. (Schedule 4 is just a classification - it's defined as drugs with have low risk potential for abuse or dependence). So going to your local hospital with proving documentation of your father's condition might obtain you some. Cannabidiol is good for anxiety, movements disorders, chronic pain and cognition. So CBD Oil might be effective? I hear people say that it is effective. I think going with the CBD (cannabidiol) is a more natural approach.
https://www.qld.gov.au/health/conditions/all/medicinal-cannabis - Queensland Government site - Medicinal cannabis treatment. If you're not in Queensland, this site could redirect you to the suitable area or at least provide some helpful information regarding the drug.
You can try for an higher level of benzodiazepines - They slow down the brain's central nervous basically. So SIV such as Ativan (lorazepam) - this goes under the tongue and melts away, it acts quite fast. It is primary used for anxiety and depression but pain management as well sometimes. Valium (diazepam) it's used to help lesser intense panic attacks and considering your father's current condition, the addiction risks probably won't be an major factor. Clonazepam (klonopin) is another commonly used treatment for cancer patients, tho it is also used for controlling seizures and nerve pain, multi-use. All will cover some level of pain, some more than others.
There are a lot of drugs out there and different drugs treat different pain. Soft tissue pain, nerve pain, bone pain and etc. Sometimes taking 2 or 3 types of medication is required to treat each one. but I would still recommend the more natural CBD one. It treats inflammatory and nerve pain as well. But that's just my two cents - remember to ask your treating doctor for recommendations.
The general rule with benzodiazepines: The more you take, the less your there. Meaning due to the side effects like drowsiness, grogginess, confusion and etc, they may not be completely aware or alert. But sometimes it's necessary.
