No, she had the key since she was a Baby, they only happened to run into each other without knowing when she scaped the orphanage and he ran away cuz he kissed his other sister
@Refure The orphan sister already had the key since she was in the orphanage. She just kept it with her at all times. I'm not sure if the brother recognized her or not, but in any case she ended up at the place where the mute sister just arrived at.
Someone please correct me if I'm wrong or ellaborate if I'm missing something.