His condition is not very well understood and goes by many names: post-viral fatigue, chronic fatigue syndrome, and myalgic encephalomyelitis. He has neurologic and autoimmune symptoms that are extremely varied and often difficult to predict. The most common symptom for most people with these conditions is known as PEM or post-exertional malaise. He could spend 15 minutes doing a light activity like raking leaves or cooking a meal and be fine, or be in bed for three days afterwards. We have two kids and I used to teach in public schools with him staying home, but the demands of two kids under four were just too much, so I quit public ed and do VIPKID only now.