Every conversation Harry has with Carlos after he's injured reads very differently if you read it where Carlos assumes Harry knows what happened with Molly.
They don't have a conversation where Harry doesn't threaten him with Molly, as I recall- I thought it heavy-handed. It's always at that point that Carlos twitches.
Harry is assuming that Carlos is such a straight-arrow that he'd feel obligated to report everything- so anything he tells Carlos isn't necessarily confidential.
Carlos assumes Harry knows about Molly, and is always threatening him casually. Also, from a Warden perspective- and Harry has been a Warden until being kicked out this book!- how rough has the war with the Fomor been? And Harry casually raises an army of Little Folk, brings in Bigfoot as backup, slaps Drakul a bit, mashes a couple of Eldar black court vampires, and finally brings down Ethniu.
Harry admires how Carlos can throw such low-energy punches endlessly, because Harry's swing-for-the-fences approach is exhausting. Now see it from Carlos's perspective: Harry can punch like Ebenezer, again and again and again and again. Why the hell didn't he take it to the Fomor? It's the Red Court all over again. Harry casually starts a war, the White Council bleeds for it, the Red Court goes after Harry personally and he annihilates them. From a distance, that's what it looks like- Harry's been holding back.