Responses
Its chapter 6 of this. :)
http://www.mangago.zone/read-manga/tsumetai_kemono_ni_kawarete/
Yes!! Thank you, thank you, thank you!!
I can only remember it has a school-age uke who's the childhood friend of a singer who treats him like a little bro. The uke visits him backstage after a concert and sees the seme walk away with an ex-girlfriend. At some point, the uke gets upset and runs away, and the seme tries to catch him from falling down some stairs. The seme is hurt now in the hospital. I think it might be with a collection of one-shots? Many thanks if you can help!