Because Charles can hear everything, pulled like a firing pin and cocked like a hammer, he will hear Erik turning each sentiment inside out in his mind, scouring the words for the kind of infinitesimal doubts that start sand grain small and work bloody welts. This is not to say that he finds none, but rather that he doesn't voice any of them, or allow them time to coalesce into the poisoned brilliance of pearls ripped from the mouths of oysters like teeth.
Instead he bends his head to Charles' shoulder very, very slowly - he doesn't cling, or cry. His eyes are still most of the way open, but so is his mouth, like he can't breathe through it, until the deep etched creases in his brow actually touch cloth. Then he breathes in, a displaced, backwards sound, and it's the best that he can make at that moment.