PAIN coincides with the swelling up of blood vessels in the brain. I ALWAYS WONDERED if the smooth muscle of blood vessels get exercised and build up stronger vessel walls and if more than brain vessels are involved.         
Research might reveal if strokes or aneurysms are less or more frequent in migraine patients. Maybe migraine has a protective blessing or not.
Only my Grandmother also had migraines and had exceptional predictive abilities although I don't rationally link the two. Migraine made reading even more difficult. My parents always said people differ in the books they read and the people they meet. I tried to fulfill the meeting remarkable people part. I was drawn to pioneers in a field, famous philosophers, psychologists, composers, conductors and musicians throughout my 20's. After that introductions grew more difficult as if youth was a passport to meet special folks. By looking at my early posts and now, you can practically see a before and after of migraine.
Today there are so many more medicines and treatments for migraines so I hope your son finds early relief and freedom.