I do like that Tachibana shows a different side of himself when he's with Tendo or when it's something about her. I also like how the author always shows Tachibana's reaction when it's about her, like during the play. However, he's really hard to read. In my opinion, Tachibana came to care about Tendou more than that of what he considers a distance for friends but since he's a bit clueless when it comes to his own feelings, he thought what he felt for her was familial love. Like since his feelings cannot be categorized as being friends, he thought it may be because he thought of her like a family. He even told Yuu that he thinks of Tendou as his imouto lololol. There's a good comment in comico in that chapter saying a person who doesn't have a sister doesn't really know what having a sister is like. So maybe, Tachibana doesn't want to recognize his feelings as romantic and settled it as feelings for family. I really hope the author gives him a bit of a hard time before she decides for them to be together. Or allow him to see Tendou flirt with another guy, probably Arizawa, and get frustrated with it. I really need to see it. If the author decides to ship her with senpai, I actually don't mind. Lol. I believe if along the way Arizawa would like someone, I think it would be Tendou. I don't know, him liking Tsubasa at this point would be anticlimactic.