My Husband (64 Years Old) Has Been Having Cluster Headaches---this

My husband (64 years old) has been having cluster headaches---this is going up the right side of his face/head. He took steroid medicine two weeks ago and last week 2 steroid shots ...also verpalmila and Prednisones ..He is in a lot of pain...( he has about 3 episodes a day that last two or even three hours - brings him to tears)... is there a doctor that you would recommend in or around Charlotte, Nc. That specialize or treat this... He has been going to the family dr. She is trying to help..but she's now on vacation..I feel I need to see if I can find a doctor that specializes in this or have seen this before...that can help him.