My mom tried Gem/Cis for about 8 weeks last year. It was HARSH. Although I'm sure I could never capture exactly how she felt on it, it seemed like she felt like she had the flu just about every day. There is no way she could have worked throughout the process. The key is REST.
She did experience a low white blood cell count several times to the point where she had to add a couple of off weeks to the regimen. It does have a tremendous affect on the GI system and it took awhile for her not to experience pain upon eating.
However, her results made the whole experience worth it. Her CA-19 marker was back to normal (after being about 1100 before) and her lymph nodes came back clean on the scan. So far, so good. I don't want to jinx her but I feel that cisplatin can work for those who are able to withstand it.
She had a major check-up at the halfway point to see if the chemo was effective. I recommend making sure that your family member gets one too so that they won't continue with a regimen that makes them feel worse without the added benefit of making them "better".
Be positive because it CAN help some!