Sometimes the world is a cruel place, and children are often the first casualty of that particular place. Izana is many things, but he isn't one to simply ditch his family and leave them bleeding out from scars inflicted upon them. He just doesn't show it in the way that one might expect.
Izana isn't an adult when his father got killed, but Zen, Zen, was just a child, practically a baby, when compared to Izana as a teenager. And you don't let your baby brother get swept up underneath the current.
So, he steered as much of the drama of the tragedy away from his brother, and tried to be somewhat active in his life, especially as their mom moved away, and Izana, the Crown Prince, was tasked with managing Clarines. Zen was young, when his brother became an authority to be reckoned with, and only a teenager when life slipped something else into Izana's door.
Zen made a friend, and if it was just a friend, as biased as that could be, it would be easier to put up with. But friends don't react in the same way that Izana has caught Zen reacting; it's as if Spring darted into Zen's life and left him sprouting up a little older than he had any right to be as of yet.
But, she's also a commoner, and Izana didn't trust himself when he was teenager, at least not in regards to attachment to other people, it was easier to rule without any smitten feelings, let alone would he trust his younger brother with such attachments. Wild from youth, wide eyed, and excited; where he once was cautious, he is no longer. He isn't afraid of her, that much is certain, but in a lot of ways, he's still learning, learning that love isn't a one way street, and it is a challenge, though it's one that Izana doesn't imagine Zen fully realizes yet.
Izana isn't interested in the folly of crushes or the mad dash of freedom seeking youth, but he does care for his younger brother. And attempts to separate the two so far aren't complete, and that does make Izana wonder whether he should force further separation on them, so that Zen might be less infatuated with her, or whether he should just accept that right now they are stubbornly in love.
Who knows what distance might do? Or whether it will make or break them? But, Izana knows in a way that his younger brother is slowly growing up, but he is still young, in the way that an older brother can see both himself in the younger and everything he isn't, but also, everything that often defines that age.
He's old enough to look at Zen as almost a son, roughly eight or more years apart, and that's enough to understand that Zen is still figuring out what growing up means, still figuring out the duty bound state of a prince, and still figuring out what or who to fight for. And in a way, Izana hopes he becomes strong and determined, not weak and easily giving in. A ruler couldn't always bend, and Zen has been a bender, one who bows his head and takes Izana word for word. Izana doesn't want revolt, but he wants to mold his younger brother, the way that their father couldn't, the way that their mother didn't.
"Little brother," Izana considers what to really say, though no words seem to suffice, "What does she mean to you?" It's enough of a question, one that Izana is pretty sure he knows the answer to, but watching his younger brother go through every last flurry involved with that question is enough of a consideration too.
"Shirayuki," He pauses, awkward at being called out, still young, "I love her. I want to be by her side."
Young and foolish, but there is a little resolve there.
"If so, you can't let your emotions get the better of you. You, as a Wisteria, are better than that." It's the closest that he'll ever say to what he's really thinking, but it's enough, as Zen pauses to take in those words, try to compare them to both his heart song, the way it sings for her already, and his own emotions.
If he chooses this path, and she does too, this won't be easy for the both of them. And Izana isn't sure right now which would teach his brother to be the prince that Izana hopes for, the prince he sees in him. But if it's walking by her side, she better be worth the crown and worth the title. Izana doesn't just let anybody come walking into the castle or into royalty after all.
And what has easily crumbled people before her is always a last resort for her, if she were to manipulate the title that marrying Zen would provide her. Not just anyone is worthy of being by Zen's side, and not just anyone can handle what that would mean.
But if Zen grows without her, hopefully, the break happens soon and hurts a whole lot less. Zen doesn't need to suffer over her for long, but if it will make him better, Izana will let even the break happen.
Zen has potential to be an incredible prince, but he's also, so, so young yet. And Izana doesn't make it a point to abandon children, though sometimes stepping aside for a moment and watching someone grow to understand through experience how to lead can be the right option. As long as you don't ditch them when they've figured it out either, even if you are merely watching them grow and offering encouragement rather than physical support.
Zen's still growing, and Izana refuses to just let him crumble from foolish mistakes, whatever they may be.