I'd be careful with meds for humans, as mine (and I guess yours) knowledge of chemistry and biology might rather poison the dog in some way. Instead of weed with THC how about just CBD? Not sure if the oil will do, but maybe daily in a month it'll bring relief. If she's late stage cancer, I'd go for higher dose of cbd and thc just as a bonus - thc might be the solution more towards the end.🤔