https://www.youtube.com/watch?v=akhf4AJoMo8 i think this is him. he's cute
and it doesn't bother me, i think it's cool that he's his inspiration for a character
I haven't read Lookism yet. But maybe the author asked Hyung Seok before he/she put him in the story? I don't see how you could do that to someone you know without informing them and getting their consent. That would be irresponsible. So yeah, if he agreed to it, I don't think it's a problem. Maybe he likes being a part of a creative process.
Artist is really inexperienced, and draws "slow" not fluid, but plot is good I guess?