Interesting that you read it that way. There are times when they do that to each other, but to me this was quite clearly a “protect me, big brother” moment.
Much like this one, from “Lemur Legs.” Chris has no idea what it is that has crept up behind him and made that sound, but as soon as the fear kicks in, where does he immediately end up?
You guessed it. It’s absolutely instinctive for him to seek protection from his older brother, and I find that incredibly sweet.