It could be many things. Best thing is to get him in the doctor, also ask the doctor for a MRI and a neurologist consult. It could be a trigger point sinus headache, TIA, inflamed sinus', inflammation, so much.
"The Walking Medical Mystery"
Too many Allergies / Too many RXs & DXs
A Rare Gem for Doctors and Guinee Pig
~Medical Caregiver and Doctors Worse Nightmare~