Hey there!! What he is going thru sucks big time. I am sure that you are handing him some caffeine first thing. He needs to let you know when I first starts. If you watch him you might even beat him to the draw on that one. Head or face rubbing can be not noticed by the CHer, but family will see it.
Other emergency measures include putting an ice cube on the roof of his mouth at the start and sucking on it. Sticking his nose up next to the AC vent of the car with the air running wide open. Running a few inches of screaming hot water in the tub to stick his feet in. Then putting a cloth on the painful area - hot or cold depending on what works for him. Some go for the shower method - using either hot or cold as their head dictates. Some rub the painful area with an ice cube too. Keep him from getting too hot. No outside in the heat work for now.
Just let him move as the pain dictates. Restless movement due to the pain is part of the condition. You don't want him to bang his head if he can help it. But, some banging is pretty common.
Please, check out the D3 Regimen in the Clusterbuster Files section. It is easy, cheap, and effective for most. It can start working in days. Lowers the intensity and length of hits for a lot of us. For some, they go into remission with D3 alone. Great stuff there.
It is as hard to watch a hit as to have one in my opinion. You feel helpless and that sucks. The emotional pain that a supporter feels is draining. Hang in there!!!! You will get this on the right track soon.