Cass keeps an eye on Spike while he coughs, to be sure he doesn't choke or anything like that. She isn't entirely sure Lucrezia or Joshua would actually help him, which is probably a bad thing to doubt, but there is it.

"There's still time. It's not cold, yet."

She's either buying Spike time or saying it's only a matter of time, one of those two. Probably the first one. Because poor Spike.