As much as he's open and affectionate with John, that's an extremele outlier that shouldn't be counted for his regular behaviour. He's just- not an affectionate person, normally, and maybe part of that was always expecting people to hurt him, but it was also just The Way Things Were Done, growing up, and he knows it's something Charlie shares.

...but on the other hand, he's not sure if he could forgive himself if he just let Charlie suffer through this alone. Trapped in this stupid fucking town with constant torture and terrified of food resources and stuck reliving the King's bullshit without knowing how intimately John and Arthur understood him.

He pushes to his feet, hands trembling a little still, squeezing them in and out of tight fists to try and loosen up the sensation as he approaches the rocking chair, creaking gently under the strangled force of Charlie's quiet sobs. And he stops beside him, looking for all the world like he's hesitating, debating walking past - and he can't deny, a small part of him is - until his arm shifts and he rests his right hand on Charlie's same shoulder. So they can pretend Arthur isn't looking at him, while he gives him a squeeze to keep him grounded.