Honestly, it's not some sort of huge revelation regarding Hyesung's feelings. I'm more surprised at this point that Shiho is straight actually )) but seeing how Gaeul's demeanor is quite similar to Hyesung maybe he is gay after all 😅
Anyway I wouldn't say Hyesung is gay per se, he's just into Shiho on so many levels. Imo it's more of a strange mixture of parental affection, siblings and bfs love all together I'd say 🤔 but maybe the author will give us some insight in the next season 🙄