I am new to your blogging site and have to say that you are some of the most informed and intelligent people online! (I have done a little lurking before choosing to join.) I have a degree in Early Childhood Development and 30 yrs of experience working with young children. I truly concur with many of you that JR has confused reality with imagination in this matter. He has to be extremely stressed about his missing sister and all of the confusion surrounding him. He is undoubtedly experiencing fear for his sister and himself. The person in black is probably a result of dreams mixed with the reality which he cannot comprehend. The person in black could in Jr's mind represent Batman or a positive character simply to reassure himself that Haleigh is OK! JMO.
Sorry, if I have rambled too much! : )
Good to have you here and thanks for your comments.