-He doesn't know where exactly she is. They're close to each other but they never meet. It was like this earlier (in chapter 15). Luck isn't on their side (at least not right now), that's the point here (it's more obvious in chapter 16).
-He didn't think she was outside and he had no idea who that guy was, he just noticed him. He thought that she found out about the house her grandfather gave her and went there.
-He has a new phone or number. In chapter 25 he said "how did you get this number?!" when he talked to his "mother". We also know that Yuju was waiting for Giju to contact her. When you read between the lines it becomes clear that Yuju doesn't have Giju's number but he has her number.
I hope this was helpful.
yup, Thanxヾ(❀╹◡╹)ﾉ~
this all so confusing, how did he know where his sister was/is? if that other just just robbed her and left her, why did her brother not find her but some if just seconds after he bumps into the robber??? like so confused, why was she looking/searching for her brother if she had a phone and a way to contact him, not to say that he knew where she would always be?!? (⊙…⊙ )