Honestly, I’d prefer if they don’t date and just stay as friends. Her current relationship with the older brother sends a message to Youta that just because someone is special to someone doesn’t mean they are romantically in love. You can have a close and special relationship with someone without having any thoughts of dating them.
It adds to the conflict and is generally an important message to have. So having them get together undermines the message of it and the conflict so far. Plus, I just think it would be a lame and lazy thing to do.