He tried to go to the hideout the workers kicked him out, I’m assuming that the story means to say that the Uncle was hiding the fact that he was letting his nephew stay on site and that’s why none of them thought of him, but I don’t know. I’m trying to get the story grace with that one and I’m assuming that the call that worker got before he found him was the Uncle calling to check on his nephew.
All the times they’ve gone to that hideout, all of a sudden he’s getting chased away by the workers? If the workers are now in that area, he couldn’t glance and see the hideout was covered by something huge and express concern? I also can’t imagine him giving up THAT easily and just leaving based on how he’s been portrayed so far. It’s all for the plot

They agreed to meet in the hideout. So why would Seunghyun not go to the hideout, notice it’s blocked by something, and inform someone? How is he still in there til morning? The uncle works long shifts like that? Why did none of his coworkers notice the kid was missing for that many hours? I guess it’s all just for the plot lol