He was a disabled child after an accident caused by a car hit and the lad hadn't been able to walk since then, he suffered from mental issues and hearing issues, and now he got abandoned by the orphanage and had no one by his side.  

“Welcome to Mounteen eh-eh Mountain Woods orphanage.” Jeonghan said with flourished hand gesture. “It’s Mounteen alright.” Jisoo interrupted him off-camera. “The name is Mountain Woods.” Jeonghan hissed at his twin.