Migraine is a symptom. There can be various causes. An intolerance of sugar can cause problems - he should try excluding it from his diet for a week to see if that improves matters. (Read those labels, some savoury processed foods contain high levels of sugar).
The most common cause, especially among computer users, is a minor neck injury. Try ice on the back of the neck (yes I know that's not where it hurts, humour me!). If that helps, see a chiropractor.