Does the bold part suggest that at any other time he would have said something nice to Lucy for {at any other time} he knew how wretched she must be feeling, and he knew that, whatever had happened, it was not her fault."?
Does “for he knew how wretched she must be feeling, and he knew that, whatever had happened, it was not her fault” only refer to the current situation and not any other time?
“Oh, come on,” growled Edmund. “We’ve got to go. There’ll be no peace till we do.” He fully intended to back Lucy up, but he was annoyed at losing his night’s sleep and was making up for it by doing everything as sulkily as possible.
“On the march, then,” said Peter, wearily fitting his arm into his shield-strap and putting his helmet on. At any other time he would have said something nice to Lucy, who was his favorite sister, for he knew how wretched she must be feeling, and he knew that, whatever had happened, it was not her fault. But he couldn’t help being a little annoyed with her all the same.