By the time they made it to the Tower Sirius was barely awake and could no longer control the shivering. He had long ago let his head rest against Remus' shoulder and he was vaguely aware that he would have sunk to the ground long before now if it wasn't for the two boys holding him upright.
He just wanted to disapear, to give in to the haze and sleep forever. That wasn't too much to ask, right?