"I'm afraid that isn't allowed," Lily says, still letting him have his moment as needed—that is certainly a way for it to get out, really, and she doesn't begrudge him the reaction he's having.

Part of her feels like she should be teasing him a bit in the good-natured way she's so capable of but the rest of her thinks leave that for later when things aren't so—

She doesn't know what things are right now, other than a mass of emotions that she's kept shoved down somewhere in her stomach for years. She's happy for him, though, in this aspect: she likes Claire, she likes Severus, and why not? They should be happy together.