Adenocarcinoma/gynecologic nature/Stage IV

My mom is 80+,  had an illeostomy 10 yrs ago (no colon, rectum, ovaries), has neuropathy from shingles for 10 yrs, stenosis in her spine, needs knee replaced but not surgery candidate.  She lives independently, uses a walker, still drives.  Has been on pain meds for 10 years for her various other pain issues.  Recently diagnosed with adenocarcinoma of a gynecologic nature with malignant lymph glands, also mention of mesentery mass.  She had a stent placed in her kidney during a recent hospital visit for pain she was experiencing.  Her oncologist indicated she is Stage IV and his goal is to keep her comfortable.  His suggested course of treatment is to begin Gemzar chemo 1x/week for 3 weeks and consult after to see how she is doing.  My sister and I realize this is not something that will get better or be cured.  We are concerned that the chemo will be too much for her and thus quality of life will worsen.  Has anyone out there experienced anything similar?  We realize everyone reacts differently, but would appreciate any feedback.   The last thing we want to see is her suffer any more than she already has for whatever time left she has.  Thank you in advance to anyone who responds!