Azula's hair grows out raggedly, for though Zuko does pity her in a distant sort of way, he refuses to let anyone take scissors into her cell. Cell is a harsh word, yes, and, no, she is not in a prison, she is merely in a psychiatric treatment ward that happens to be connected to a prison. This means that unlike the war criminals and traitors and murderers in close (if unknown) proximity, she is well fed and well taken care of: she has a bed instead of just a floor; she has her own private bathroom; her clothes are clean and well-fitted, if unadorned. She has no window, for the most obvious of reasons, and she has no books, for the simplest of reasons, but aside from these deprivations her "residence" is very comfortable.
Despite these luxuries afforded to his sister Zuko is uncomfortably aware that "psychiatric treatment ward" means "insane asylum" and that "insane asylum" may as well mean "prison." Not that he would object to placing her in prison. In all honesty he would probably prefer it that way, the way it should have been. If she were sane, and locked up tightly for fear of escape and treason and a threat to his throne, he could be wary of her; their relationship would be normal. (This is not the problem and he knows it.) What it really comes down to is this: if she were sane, he could hate her without hating himself. As things are now, she has been reduced, pieces of her pared away until there is hardly anything left, and what is left is not pleasant, not that she has ever been pleasant. The insanity is so undignified, and that is what bothers him, niggling at his conscience. She is no longer Princess Azula, his plotting and manipulative and violent and sociopathic sister and the heir presumptive; she is simply Azula, a prisoner/patient who manages few coherent words on her best days and is inclined to bite anyone who enters her cell, if she does not burst out in giggles first. She is no longer what he hated, and he knows, on some level, that it is wrong to hate her broken, left-behind shell of a psyche, and yet upon the sight of her he cannot force himself past his enmity.
Guilty, and then resentful of her, for making him feel these things, he visits her occasionally. (By occasionally of course he means no less than thrice a month, and often much more than that. It is far more often than he visits his father.) Visiting Azula goes one of two ways. Either he sits outside her cell, back against the door, listening to her frenzied shrieks and vile laughter and, depending on the time of day, her utter silence (they drug their patients well, these people here, and for her they focus primarily on dampening her energies at midday, when her firebending would be strongest if she could think to firebend), or he goes in.
On those days, few and far between, she never, ever recognizes him.
Often, she does not even see him, and then for a moment it is easier; after that moment he hates himself for thinking such a thing, for thinking cruel thoughts towards a helpless patient who is not, he reminds himself, his sister, but is- he cannot help but feel- his responsibility.
When she does see him, her reaction depends on her mood. Sometimes she snarls and tries to bite him (sometimes he lets her, thinking perhaps it will assuage his guilt) and sometimes she giggles and plays with his hair, and it takes all his self-restraint to keep himself from smashing her skull against the metal door, because this is not his sister and he hardly knows what else to do.
Once, he brings Mai with him, and that is a mistake. She is supportive- of course she is supportive, in her own way- but she doesn't understand his dilemma. No one else would catch it, but he sees the involuntary hint of a smirk in the corner of her mouth when she first sees Azula, giggling mindlessly, her hair lank and long and unkempt, thin and bony and barely-there. The bile rises up in his throat and Zuko nearly succumbs to an urge to end it, right there, break up with her for good this time, but he doesn't.
After that things are different between them. He is merely going through the motions as he becomes more and more disenchanted with her, and his antipathy grows daily, and he thinks she doesn't notice. He hopes Mai doesn't notice, because he doesn't want to hurt her (but that is not the truth, he hopes she does notice, so she will break up with him and he won't have to do it himself.)
He wants to talk to Aang about all of this, because he is sure the Avatar will be understanding and helpful, in true airbender fashion, but Aang is far away, on a distant island, mediating a dramatic dispute, and Zuko realizes he doesn't want to talk to Aang anyway. Aang would simply urge him to let go of his hatred of Azula (far easier said than done), tell him to talk things over with Mai, and go off on his merry idealistic way. Idealism is all well and good, and Zuko envies Aang his unwavering certainty when it comes to morality, but Zuko is the Fire Lord and he lives in the real world, where every decision has advantages and disadvantages and he never quite knows what the effect will be anyway, where every position he takes alienates and inspires hatred from someone, where he must use the proper channels and handle the bureaucrats and negotiate with the diplomats and can never, ever say what he is truly thinking. Zuko never gets to swoop in, end a crisis, and swoop back out, leaving the inglorious aftermath and reorganization to someone else. He is the someone else.
Being Fire Lord is not at all what he once imagined, all war councils and parades. It is unglamorous, and it is unpleasant, and it is his job. There is no one else in the world to do it, and that only intensifies his worry and his undirected anger.
Aang is not the person to talk to, and Zuko doesn't know who is. He considers Iroh, but only briefly; he does not want his uncle to worry. Let him enjoy his retirement- he deserves it. This decision leaves Zuko uncertain: if he cannot talk to Aang, and he cannot talk to Iroh, he is left with essentially no options. He does not exactly have many close friends (being Fire Lord is a rather overwhelming demand on his time and attention.) He thinks Katara would be helpful- he knows she understands the disparities of knowing what is right while feeling overwhelmingly that it isn't- or even her brother or Toph in a pinch, but he hasn't seen any of them in weeks. The Fire Nation isn't the only one that needs attention. Sokka, Zuko knows, is busy rebuilding the Southern Water Tribe and making sure the North and the South remain connected; Toph has opened a school of metalbending; Katara is, Zuko imagines, with Aang, on an island in the Earth Kingdom. Technically, she is a Water diplomat (though that is an honorary appointment meant only to raise her above peasantry and allow her to travel comfortably) and has no place in an internal Earth conflict; as she is the Avatar's girlfriend (how bizarre that sounds), however, he imagines no one quite minds.
A knock on the door pulls Zuko out of his musings, and he rises from his chair. "Come in," he calls out, a hint of weariness in his voice, as he turns to face the door. The door opens and a servant, dressed in fiery crimson, kneels before Zuko, presenting him with a missive. Zuko thanks the man absently and unfolds the rich, smooth paper, and after a moment he smiles at the news: an envoy from the Water Tribe is due within the week.