For my mom who had small cell lung cancer, she did four different regimens. She had a "complete response" to the first line of treatment but then the cancer came back in 6 months and had expanded to her liver. The second line of treatment was amrubicin which was a clinical trial drug. She had a huge response to that and everything was shrinking. She would have kept doing that drug however, she got pneumonia and missed one of the sessions by more than 2 weeks. As a result, she had to be dropped from the clinical trial. They waited a month and did a scan and everything was growing again. She did Topotecan and the cancer got bigger. Then she did one more clinical trial involving Taxol with CBT-1 and no response. We were told that the further along you get with trying different medications, that your response to them becomes less likely. I really wish she could have continued with the amrubicin because it had very few side effects and was working. It is possible that your family member will have a response to the new medicine particulary if it is in a different "family" than one previous tried. My mom was always ready to try the next medicine because she wanted as much time as possible with my two sons. She just wasn't ready to go yet and I think since she had huge responses to two previous medicines, she always held out hope that the next one would work too. All you can do is talk about all the pros and cons and let them make a decision. My advice would be to go somewhere for a few days in a new environment.....a lake house, a beach house, the mountains....anywhere to get away and think more clearly to make a decision. When my mom was making her decisions for the 3rd and 4th line of treatments, she felt so awful already that she didn't have much to lose in order to try another medicine. So if the person is feeling good, then you have to decide if they want to go through chemo side effects to have another few months. My mom was already so sick with her liver being affected that we knew she probably wouldn't have much quality of life if we didn't do anything.
I would recommend looking into some homepathic medicines and maybe even meet with an herbalist/homeopathic cures person. You can do an internet search for your area. If you live in VA, I can recommend someone. I wish my mom had explored that route earlier.
Good luck and take care.
Laura