Keylime,
Is he taking any meds like Canasa or anything? Those can cause headaches and usually MD's/pharmacists don't tell you that until you say "you know I've been having headaches..." Anyways, this is probably not great advice but I take Excedrin Migraine and on occasion I will take Advil. Sometimes I have such headaches that taking the Advil once won't kill me but will alleviate the headache. Make sure to take it with milk (if he can handle that) or with some food in his stomach. I've had plenty of bad flares but none that I feel was caused nor worsened by taking Advil.
Becky