why is Kazatora adamant about Nozomu's adoption?

aah. so it's because father ootori 'implied" that a brother-pair would boost the theater results. kind of a twisted family.

Um no. Thats why HIS dad wants it. He wants to be with Noomu forever and always and thats is the easiest way to do it. Tjis way he's doing two things at once:pleasing his father and getting Noomu.