On the willows there, we hung up our lyres

He wants to say something -- he wants to thank Claudius, tell him how much he likes it when Claudius tends to his hair, how much it makes him feel like a treasure, one of the precious objects on Claudius' vanity. He wants to tell him that he'll be all right, that he'll get better. It's too much right now, but later it will be better.

Instead he stays quiet and tries to memorize every moment -- every second, because he can count them now -- of Claudius' care.