I have never known headaches to last an entire week. He must have a head shaped like Megamind for that to happen.
I'll show you 3 different situations:
1) Years ago, I had a recurring headache for almost a month. I would wake up fine and, about 2 hours later, I would have a headache. Every day, without fail. Until one day it simply didn't happen. The only difference was that I wasn't consuming the brand of butter I had been used to for years. Moral of the story: that brand that I had been using for years simply started using a dye that I hadn't used before and I had some kind of intolerance to that dye;
2) I had a cousin who had a recurring headache problem. For months. No medicine could help. After many medical appointments and tests, they discovered the problem. It was a brain tumor. He died on the operating table.
3) My grandmother used to say when I was a child that a headache indicated "a guilty conscience".
I would say that BD may have one of the 3 cases. I would bet on the third.