This chapter plays out like a comedy after the seriousness of Kei collapsing and being taken to the Hospital. In fact I don't really understand why being IS would cause that, but if they hadn't been taken there then it wouldn't have been discovered. The ending is pure farce however, "You can't continue being a guy because I've bought girl's clothes for you" WTF?
For a more serious look at being IS
https://mangadex.org/title/fec4cc5e.../is-otoko-demo-onna-demo-nai-sei?tab=chapters