ALL OF THE DOTING. Kazuaki will probably be doting on Nageki but YES let's do this. He will bring her tea. :D They can get to talking, and Kazuaki has had practice at reading people (thanks to Nageki), so I think getting to know each other's true personalities is doable!

As for Yuuya, they never seemed to interact very much in canon! But we can just go with the flow and see how their relationship goes once "oh my god my baby brother's in a coma" isn't on his mind. :D