I think Hyesung is worried that Byul might end up like him in education as well since Hyesung couldn't catch with studies much just like how he worried about Byul hating him cuz he left Byul when he was a baby and he even hated that his own mother left him so he was mad that he did the same thing to Byul.
I think Hyesung is worried that Byul might end up like him in education as well since Hyesung couldn't catch with studies much just like how he worried about Byul hating him cuz he left Byul when he was a baby and he even hated that his own mother left him so he was mad that he did the same thing to Byul.