
I think that was the first time that dohyun said his whole name... Σ(っ°Д °;)っ

You are right. I wonder if this is to signify that Dohyun finally remembers Sungho. Like fully remember him. That flash back we saw in chapter 40 was Dohyun's memory and . . . maybe it's just me but it seems like he was really fond of Sungho.
Dohyun skipped out on his part time job to be with Sungho and Sungho skipped out of Cram school to be with Dohyun. It was Sungho's suggestion too to boot.
Sounds like Sungho is from a rich and educated family.

I think this is one of those lost in translation things, because in the raw Dohyun called him Jung Sungho as early as Chapter 20, and then again when he was begging to be let out of the warehouse. I can't find exactly where he learned the last name or any earlier mention, so maybe he remembered when he had the flashback in Chapter 15-16.
Dohyun really liked Sungho, though...that I believe. It wasn't just free food. Sungho saw through his carefree act and looked after him when he needed it, and didn't ask anything in return other than his company. That probably meant a lot to Dohyun, who had a shallow relationship with his other buddies and family that had no time for him. But it feels like it's very difficult for Dohyun to show the smallest vulnerability to anyone, so of course he would never show it.

What the actual fu*k?! The waiting really paid off, cause this chapter was genius! I was like: Ok, now he is going to realize what happened and help bum
Then: Come on. Wtf? He really lost it completely now
The back flash with his mother scared the shit out of me and i was generally laughing the whole time...
I´m going mental because of this... Σ(っ°Д °;)っ
I'm so anxious, because I am guessing that this is just the calm before the storm... °~°