Responses
Hopefully aside from them telling byul that he was abandoned by his mom, they also told him how his dad graped his mom resulting to the pregnancy, no? cuz that would be one sided if they didn't. (also hyesung did not leave him for 1-2 years, it was just months, and im not justifying his actions, just informing)

Why are you all hating Byul ???
The boy had learnt that his mother had signed a contract and didn't wanted him when he was like 1-2 years old and that was a huge shock for him,he was a BABY and that truth ,the pain he kept inside all those years...and now you pointed your damn fingers on him because he lost his temper and shouted to his mom????
He has every right to talk to whoever he wants,if his grandma(or anyone else) treat him with care,love and respect why wouldn't he talk to her(or them)???