Hello, Nausea and fatigue can be due to stressful lifestyle, lack of sleep, excessive alcohol use, too much caffeine usage, lack of exercise, salty meals, liver dysfunction, hypoglycemia, dehydration, bowel obstruction, etc. He is suggested to take a short break from work, take plenty of sleep, he should relax while staying well hydrated. He should take home made nutritious food, water, soups, juice, ORS so that the body electrolyte system is maintained. Make sure his vitals are normal ( temperature, blood glucose, blood pressure). He should stay away from addictions if any. He should be clinically examined by a GP. Get Liver function tests done. Urinalysis and stool examination (R/E and C.S), imaging tests. He will be treated accordingly. He should take boiled food for a couple of days to help liver detox, take home made nutritious food with well cooked whole cereals, veggies and lean meat. He can take fruits and berries in custard or porridge, avoid taking it raw. He should take small portions multiple times a day. Avoid oily, spicy, fatty food, red meat trans fat & full fat dairy for a couple of days. He can take PPIs & liver tonics for better digestion. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician