It's madness. It's madness and he wants to stop him - has to stop him - but he feels helpless and powerless. For someone who is over a thousand years old, feelings of helplessness and powerlessness have become unfamiliar and more disconcerting than they should be. He raises his voice, he protests - he says everything and anything he can to try and stop him from suicide, but it's useless.
He breaks down like a child, blood streaming down from his eyes. He's not old and mature and invincible. He's not the predator that is feared and hated. He's just a lost boy, more afraid than angry.
He knows, somehow, when the sun comes and claims the life of the one who had given him a second lease on life. Resignation takes over when he awakens the next night, cold and numb and well and truly dead. He needs to feed. He needs to see her. He needs to clean up the mess. He needs everything. He needs nothing.