Frequent headaches - can anyone help?

There is certainly some type of 'wind up' in the nerves and possible blood vessels that supply that side of his face and head. This can come about from a lot of different things, but common offenders are food allergies, immune imbalances, yeast, mold, parasites and such. A 'wind up' in the nervous system can come about through repeated exposure to a stressor. Fortunately, this can be reversed if his particular pattern can be evaluated properly. You may be able to control the symptoms somewhat and reduce the pain, but to actually eliminate it for good, you will need to take a neurological and metabolic (internal function) approach. Otherwise, you are just masking the problem with drugs.