Headache and facial pain manily around right side forehead and eye

Hi,
My father is suffering from chronic pain in the headache and face from the past 45 years.

Pain is happens at different locations of the head and face[Right side, full head and left side face if serve sometimes] mainly on the right side of the head around forehead and eye
and cheeks not in the jaws.
Pain does shift location while is happening, its origin seems like sometime the from full head or right side forehead, then followed on eye and cheek.
Pain feels like knife stabbing on the right side forehead when originate then needles pain, or something obstructing in nerves behind right eye and cheeks with serve pain.
Its sometimes difficult to explain the pain.
he is being diagnosed with chronic migraine and TN etc.hemicrania continua ruled out but no treatment worked so far
no medication, gaama knife, botox , never blocks like super-orbital/ infra orbital injections. He tried Gabapentin and few others too, no relief.
Currently is on Lyrica(Pregabalin).

Please , if anyone can help in suggesting some good treatment , medication, clinic , hospital, any good doctor, any thing useful information to help him that will be great.

Thanks
Ritu