Castiel offered Dean a small smirk, despite the seriousness of the situation, amused to see him laughing like that. Anything else he may have been about to say was lost when Claire handed Ruby back her knife. Castiel couldn't deny that he had tensed when Claire moved closer to the demon, and let out a sigh of relief when it became clear that no more blood was being shed.
It didn't change anything, and it never would, but at least that was that for tonight.
He watched Ruby go, inwardly praying that she truly would go straight home before he focused back on Claire, looking at her with the same defiance she'd been showing.
"I can do it all myself and you need to get some rest," he told her firmly, his gaze pointedly looking at the injuries she still had. "Claire, you were killed, powers or not, you need to rest. And," he added, more than prepared to sink this low. "Dean still needs to rest and if you're moving about then he'll be tense so sit, recover, call Faith." Phoning people was a nice, non active activity. He pointed at the space next to Dean with a serious look.
"I will start working on healing these people," he then decided to maybe compromise a little. "Once you're healed and you've contacted who you need to contact, then you can come and help, but only if you're strong enough."