Remus gave him a sympathetic smile when he said it didn't hurt anymore, and he would have told him the honest truth about that but he didn't have to. Arcturus had the situation well in hand.
Sirius pulled back the blanket, and Remus kept his expression as calm and neutral as possible given the unnatural angle of the poor boy's arm.
"No, that's okay, you don't have to move it just now," he told him gently. "Now we can't just leave it like that, you don't want a wonky arm forever, hmm?" he continued in the same tone. "So I'm going to lift up your sleeve and take a proper look, okay?" he told him, gently doing so as he spoke. It really didn't look good.
"Right. It's all going to be magic, okay? I'm not even going to touch you. I'm going to straighten it back to normal, and that might hurt a bit, but then we'll wrap it up and keep it nice and snug until we can get that other potion for you," he was telling him, as he ran a hand over the broken area, about an inch or two away from his skin but true to his word, not touching him. He could feel where it needed to snap back, and the quicker it was over with the better.
"Okay, here comes the straighten-" he told him, and with a quick turn of hand there was an audible crunch as the bone ground back into position. Philip gasped and hid into his father's side. Quick as anything, Remus then pulled out his wand and tapped it against his arm. "Ferula," he said, and bandages spun up Sirius's arm, strapping it tightly to a splint.