There is hope for people who cannot tolerate pain medications. One process involves doing relaxation exercises to turn down the stress  response. These can take the form of guided breathing, meditation, guided imagery, self hypnosis,  massage therapy, etc. Why can this be effective? One reason might be that pain evokes the stress response which in turn releases chemicals that can stimulate the pain receptors. Over time this reaction can leave some individuals increasingly sensitized to pain. 

Relaxation exercises allow one to remodulate the stress  response, reduce anxiety and stop the release of harmful chemicals.  Relaxation also reduces stiffness and increases mobility and therefore the supply of healthful chemicals to the  injured  region. Massage therapy , for instance, can be used to reduce tension, soothe the nervous system and increase circulation.Other possibiities include applying warm or  cold compresses, ultrasound, transcutaneous electrical stimulation (TENS), acupuncture and water therapy.

How effective these options are depend on the individual. Studies show, for instance, that 15-20% of the  population with moderate to severe pain can effectively  eliminate pain through self-hypnosis. Some individuals fare very well on  these techniques while others do not. It's a  very difficult situation but there are options - good luck with your mother!