CS in large quantities is known to sometimes cause a Herxheimer reaction (nausea, aches,chills, fever, tired,loss of appetite etc.)This is from massive amounts of virus/bacteria/fungus being killed by the CS. This is a good thing in a way because we know the CS is working. The body is trying to detoxify itself as fast as it can hence the tiredness and loss of appetite. Similar reponses are often reported with chemotherapy. If he can stay the course he should see results and start to feel better in perhaps a few weeks. A few days is too short a time to see results with a disease this advanced.