Crowley had his doubts about Castiel, and how helpful the angel might be, but Ruby didn't need to hear all of those. She had probably thought of them herself, if they were being honest.
"I reckon most of them will be happy to go for it, some like Khan might want to know how we're going to prevent Lucifer and Michael getting out and I don't actually know if we'll have answers for that, but we'll try to put some safeties in place. I reckon the biggest lot of bickering will be the 'but I love them more' whining when they're deciding who gets to play in our little ritual." And really, he didn't give a shit on that side of things. Ruby and Juliet would be key, beyond that, it didn't really matter as long as there was someone for everyone.
He listened to Ruby talk with a small smirk on his face. "Does seem to be a trait of that family. Urgh, you're a Winchester," he pretended to scowl. "Oh well, no one's perfect. Except me, obviously."