He tries not to think too much on your humanity. Your little brother—adopted of course—is a ghoul and unable to fend for himself, and that’s what matters. Ayato had met you both by chance, and he placates his growing unease at such close proximity to a human by telling himself he’s only concerned about looking out for the kid. With his resources thanks to Aogiri he can ensure the boy is fed without you having to resort to less than savory methods and risk exposure of you both.