Responses
Realistically he can't have gone that far. It's not like he is the physical state to go traipsing back to Dojin's or his friend's places, whilst wearing his pyjamas. Nor has he any money presumably for transport. I'd imagine the next series shows that he's still in the hospital, gets discovered by Heeso or Dojin then they start to have a conversation, with Dojin saying all he wants to say honestly..... and maybe Dojin can support Hye-sung to go see his son.
How long was Hye-sung left alone after all? In the time when Dojin was with the baby and then went to smoke.
When I came to the hospital unexpectedly and was left alone, I always feel like I want to howl, just because I was alone! Even the annoying bed neighbors, I was grateful for, so I did not have to be alone anymore.
Hye-sung thinks Dojin just cared about him for the baby and now he didn't stay at his side...