I don't really know what to say about the weight loss issue. As I wrote in my post, I started out 25 days ago 75 pounds overweight. I have now lost 22 pounds, but have lost nothing at all in the past 5 days. I don't know why this is, but am trusting that my body knows what it is doing. Pepe has posted that he fasted once (I think) 40 days and lost just 20 pounds. I think that it is possible that if your relative is underweight then perhaps she wouldn't lose too much. I suspect that she may have to increase the number of MCs she has per day, or else increase the syrup in each glass, as that's where all the calories are (50 cal/Tbsp). However, given that this is my first fast, I am not the best person to hand out specific advice for someone with a grave illness.
My detox symptoms were very mild compared to some that I've heard about: low-grade headache for a couple of days, currently tons of phlegm that I am coughing up (I've read that that is a symptom of your lymphatic system clearing up), and some rather annoying leg pain at night. Other than that, it's been very clear sailing. On a very positive note: my craving for alcohol was gone by day 7. If I had quit then, I would still have been ahead.
Best of luck to both you and your relative. This was the best decision I could have made. And, if she is ready to quit, perhaps it is for her too.