in the eye
Byakuya knew what other Captains might have said, if he had been able to discuss the matter with them. If he had considered discussing the matter with them.
Fortunately, such a thing was unnecessary.
It was not as if it was important, after all. While there was a vague similarity between Rukia and Hisana (he would be the first to admit it, if such a thing should ever be appropriate, which it was not), he was surely the one who knew them both best. He could remember every detail of Hisana's face and body. He looked at her picture every day. Rukia was entirely different.
If there should be a reason that he chose not to look at her, then he supposed one might, under some circumstances, call it guilt. After all, he was the one who had failed to realise Hisana's secret. He was the one who had let her wear herself away as she sought for her lost baby sister. He was the one who had promised to find that sister -- but too little, too late.
Ukitake's request that she be promoted to a seated officer had provoked a curious blend of emotions. On the one hand, it was pleasant to know that Rukia deserved such a rank. (Not that he expected any less of her: she was a Kuchiki, after all.) On the other hand, it was obviously out of the question. She was far too young and inexperienced for such a position. There was too high a risk that she would be hurt. He owed it to Hisana's memory not to put her sister in danger.
He was sure that Hisana would have understood. He
could imagine her laying her fragile hand on his and saying, Husband,
please keep my sister safe .
And there. Another piece of logic that utterly defeated any argument that Rukia was like Hisana. He knew Rukia's face by heart now, every line and shadow, every suppressed twitch of her lips, every stiffening of her jaw and wrinkle of her forehead. He watched her. He didn't let her know, of course, but he watched her. He watched over her. He was her brother now. It was his duty to watch over her.
But since there was nothing to discuss, then there was no reason to tell her, and nothing to say.
Least of all to Rukia.