I am truly sorry to hear about the suffering your mother is enduring. I went through a similar ordeal with my mother and can also empathize with your suffering.
This is my personal opinion: I believe that THC should not be feared by cancer patients, especially patients suffering so greatly like your mother must be. I firmly believe that cannabis is one of the most valuable medicines in this setting. I believe that there is a very good chance, without knowing more about the situation, that the benefits would decidedly outweigh the risks. Of course, extra fall-precations should be implemented.
Cannabis is a very effective anti-nausea medicine. However, unfortunately in this situation, it is the THC that is, by far, most responsible for alleviating nausea. Also, the morphine may be exacerbating her nausea. Cannabis has been shown to work well in conjuction with opiate medications, such as morphine, allowing pain patients to reduce their dosage of the opiate medication. Taking some cannabis with the morphine would be a good strategy to address the nausea and pain simultaneously.
Products with higher concentrations of CBD vs THC, such as 20CBD:1THC, will lessen, or even eliminate psychoactive effects, and thus should not increase fall risk. However, products with similar levels of CBD and THC, such as 1CBD:1THC, would be more effective at treating pain, nausea, insomnia and depression; however, would increase the fall-risk, so extra fall precautions should be implemented.
I recommend formulations offered by Care By Design. I have no affiliation with them. However, I like that they use the whole plant when making their products, rather than isolating only THC and CBD; offer a variety of ratios; offer all routes of administration, other than combustion; clearly label their products in mgs of THC and CBD per dose; and are elatively easy to find. You can start with the 18:1 formulations, then increase the THC concentration if needed, e.g 18:1 -> 8:1 -> 4:1 -> 1:1
Tinctures – effects take 15 to 30 minutes to reach peak effect; effects last between 2 to 4 hours; should be held under tongue 60 to 90 seconds before swallowing; tend to be more expensive; offer more variety of ratios and accessory cannabinoids, such as THCA and CBG
Vaporizing – effects are felt immediately and peak in 10 to 15 minutes; effects last between 1 to 2 hours; much more convenient; tends to be much less expensive per dose; less variety of ratios and rarely can be found with accessory cannabinoids.
Edibles/pills – effects felt in 20 to 45 minutes and peak in 1 to 2 hours; effects last 3 to 5+ hours; the most convenient method; offered in a variety ratios and often can be found with accessory cannabinoids.
Please let us know if more clarification is necessary. I would be more than happy to meet you and your mother for a consult. Your mother, you and your family will be in my thoughts.