If you're talking about his friend that sticks by him, then no he's not romantically interested in Yeonwoo. Honestly he's just very protective and word about him because of stuff that happened in the past that gets covered later in the story
If his best friend NO NOT AT ALL, so far only a girl was shown confessing to Yeonwoo. However Yeonwoo's relationship with his bff will be really misunderstood by someone, they have a very deep past, and I suggest you to read it for you to understand.
Please read it whole before making an opininon, and as ppl above said theres no romantic feelings involved
BUT BEWARE ITS TRAUMATISING I STILL HAVE NIGHTMARES
Its still AMAZING though but u will SUFFER
He's just like an overprotective brother, and there's a good reason for it
Does that dude like Yeonwoo? I heard from someone but so far I ain’t liking him, he’s weird imo. I just skimmed a few pages