As my ex-wife and my kids mom has breast cancer and it was a difficult time also. I can only imagine the type of pain that happens and i'll pray you get better. More peace and love is needed here and i wish you the very best!

My mum and dad both died from cancer in their bones that had spread from other organs. My mother's was much more extreme than my father's, and from witnessing both of them rot, I can tell you that there is next-to-nothing the doctors can do beyond a certain point. It is not their fault; medicine merely its limits. What happens is that you'll be administered extremely strong pain killers at high doses, you'll build a quick tolerance to them because they will stop touching the pain after a while as the cancer spreads, the effectiveness is gone, and you'll need even stronger drugs to the point your brain is shot like a junkie. I seriously feel for you and I'm sorry to be the barer of such news. This why I so strongly support euthanasia, provided that it's practiced under the right circumstances. I can't tell you to stay strong because experience has taught be that that vicious disease will wipe you of everything shy of and including your soul towards the end of the road. That said, for being dealt such a cruel hand of cards, I wish very much for your final journey to be quick. I must applaud you for remaining an angel through it. If there is a God, it's mind is fucked up when it comes to the randomness with which it allows all walks of life to suffer. May the peace be with you.

It's his brain.
The problem here is that we live in a fascist society controlled by various interests who are hostile to freedom. In a free society if I want to buy enough morphine to put myself into an opium fog, as Coleridge did, etc. etc. that should be my right, sick or healthy---but if sick, it is pretty much sadistic to deny people opium/morphine ad lib.

As for the OP, have you tried high dose cannabis oil? You can basically take as much of that as you can get your hands on, and it is non-toxic---at most you'll just pass out, which might be a blessing. Google "rick simpson oil", "full extract cannabis oil", etc. etc. Basically, you want to get a pound of weed, extract it with pure ethanol (which thanks to the aforementioned fascists is difficult to purchase in BC, but it can be had in Alberta), boil off the ethanol, and eat the ~70g of whatever you get out of that as quickly as you can. Repeat as needed. Smoking pot won't be enough---to get proper analgesia from marijuana, you need to eat large amounts of it.

https://www.painbc.ca/chronic-pain/clinics-and-services

Maybe one of these can help you.

Sorry to hear about your pain. I hope you find some relief.

This is unacceptable. Find a new doctor, keep demanding better care. I suffer with chronic pain and know how difficult it is to get effective pain relief but end of life care evenmoreso should not be a struggle. That said, during a bout of terrible shingles in my head I was given some strong opioids and found myself sick from the drugs but In excruciating pain without them. Neither provided any quality of life so finding the right drug and dose is a fine balance. I hope you are able to find something that works and allow you to enjoy whatever time you have left.