I don't know if anyone has mentioned this (only read 3 pages), but anything with zero carbs is very hard on the liver because even in ketosis, the brain still needs ~25% of its energy usage to come from glucose (why this is though, I haven't been able to find out why). This means that your liver will have to convert protein into carbohydrates (glucose), mostly for your brain, which is why your blood glucose levels stay normal on a ketogenic/carnivore/ZC diet. This can cause a fatty liver over time though, and the long-term risk for this is cirrhosis.
The liver can fully regenerate though within about 6 months from practically nothing. Well not really; I heard that if you cut out half of the liver, after 6 months, it will be—albeit in a deformed shape—and will have about 80% of its functionality. This is for a really healthy liver though, not sure about a bad one.
The remedy for this from what I've read (and this is just me connecting 2 completely unrelated things together, so take it with a grain of salt), is fasting. My understanding is that when in a fasted state, your body is primarily burning fat. As glycogen levels are depleted however, your body will need to use protein and convert it into glucose (which I mentioned before), BUT the protein it will prioritize first will be scar tissue and excess skin, so long as you are placing SOME kind of physical stress on your muscles periodically throughout the day, during the fasted days. Then there's the whole science with autophagy and mitochondrial biogenesis (which I think would help CFS/ME symptoms greatly since mitochondria are the primary producers of energy), which is essentially when your body will recycle and/or digest all the lagging cells/cell parts, in order to keep only the most efficient and productive cells alive during the period of starvation (fasting). Then, when the fast is broken, your cells will divide again to replace the lost cells. And because your body had prioritized the healthiest cells first, THOSE are the cells that will be dividing and replacing the lost cells. In other words, you are replacing all of your bad cells with good cells. Even further, your body will induce mitophagy (same thing as autophagy but specific to mitochondria) and when in a fasted state form more mitochondria as well (mitochondrial biogenesis) giving more energy; read about AMPK, mTOR and insulin.
Thinking about this further, I would guess that it also depends on how bad your liver is though. If someone needs a liver transplant, then this might make things worse. But it could also get better. I don't think anyone has really conducted any studies on this.