
Don't forget Yujin used to suffer in his love life before setting things between him and Ei. Now, he is happy and know very well what it's like to suffering from lack of communication and misunderstanding. I think he's a nice guy under the shell of the cold hearted businessman. I think he loves his brother and maybe Shingo too (even if he's jealous because of Rio) so he just want those two to speak. If they still want to break up, he will accept it but if there is a tiny chance that they could make up, he would do everything possible to help.
That's what I think (I take a liking to Yujin).

Like I said in a precedent post, I d'on't really feel that it's a cold look (in chapter 9 his look is the coldest I have saw in the Kuroneko serie). The firts time I read, I feel like you but in reading it again, I find his look is perhaps a little cuning but mostly happy. Shingo fly here to see him so he understand that Shingo still loves him. But waht I fear the most is that he will tease Shingo to get revenge and that would be bad...

I hate to say it, but it feels more like a plot device that was needed to get Shingo to the US. It would have been better if Yuujin had just given him the ring, and told all the trouble Keiichi went to, and it was Masayan who convinced Shingo to go and talk it out, as they had that kind of relationship. The end result is the same, but more true to the characters supposed level of acqaintance.
Something that still bothers me is Yuujin's attitude in all this. First off, he gives the ring to Shingo, despite Keiichi telling him not to. Obviously the ring was ordered when both felt differently than they do now. The circumstances have changed. The efforts that Keiichi went to about the ring can hardly be Shingo's fault, yet that is the feeling I get from Yuujin. Moreover, if Keiichi didn't want to give him the ring himself, then I can't see why Shingo should be obligated to return it in person. And if there is someone Yuujin should be confronting with the ring it should be Keiichi, his own brother, not Shingo.