People who are Eminem fans?

So I was just wondering, I'm reading this site about Alaina Mathers (Eminem's neice/adopted daughter) and it says she has a twin brother that she isn't allowed to see. I was just wondering why she wouldn't be allowed to see him and why Eminem adopted her and not her bro. Is this information true or did someone make it up and if it is tru please answer. Thanks :)