Welcome to Healthcare Magic!
Yes, I agree with you that your friend drank too much alcohol. Headache and fatigue
are common withdrawal symptoms
. In addition, not taking adequate food and water for four days also adds to the ill-effects on the body. Ask him to take lots of water and also to replenish his salt loss if he is having diarrhoea
. But if the symptoms do not improve over a couple of days, he should see a doctor.