I also have daily persistent headaches and it is a nightmare. Not sure what your son has tried already, but I have found that a low dose of amitriptyline and 1.0 mg of guanfacine (taken before bedtime) help with frequency and severity of headaches. I am also trying cognitive behavioral therapy to manage secondary symptoms of depression and anxiety and help with pain management (for the headaches and my other symptoms). I really hope he finds something that will help.