A lot depends on the kind of migraines he has... what triggers them. I was given a prescrip (imitrex) for mine, but it made me feel like my skin was crawling because of the vascular effect it had and only lessened the migraine. I decided it wasn't worth it.
Excedrin is pretty crazy stuff, taking too much of it can give you a "rebound headache". Has he tried Aleeve? It's an anti-inflammatory, I've had a lot of success with it.
You might also try to get him dosed up on B vitamins and Magnesium to make his nerves healthier, more resillient. (healthier nerves = less pain) It's made all the difference for me. Since you now know that it's migraines, I'd suggest finding ways of avoiding them naturally, finding things you can do preventatively. Regular sleep habits, avoiding food with sulfates, etc.
Good luck! I hope you find what works for you.
T.