"Account Closure"

Q u o t e:
I think blizz understands a 4 year old doesn't have his own email

You had a discussion with your 4 year old brother and you both decided that you'd share a B.net access since you live together? That is a fairly impressive level of vocabulary and comprehension, Sixty.

Lets get this out of the way. As you know only two people may access an account, that would be one adult and one minor child (that the adult is the parent or legal guardian of). If there are multiple children involved that would mean that the parent would be registered to both accounts and each child could only access a specific account.

Child A could access Account A, and Child B could access Account B, but Child A could not access Account B or vice versa.

If the Battle.net account is in your parent's name then it sounds like everything is good and this isn't really an issue. If the accounts are not though, I highly recommend that you, along with a parent contacts our Billing and Account Services department. They should be able to help.

Now, as to the account closure. It sounds as if your brothers account has been compromised. Meaning someone was able to acquire their password and account information and log in. The 50 level 1 characters were likely used to spam gold sales advertisements, which is why the account would have been closed, because it violated our Terms of Use.

Contact our Account Administration Department via the e-mail registered to the account.

Account Administration
Webform: https://us.blizzard.com/support/webform.xml?locale=en_US
Wowaccountadmin@blizzard.com

The two of you should also review the following thread and make sure the account and computer is secure.

Account Hacked? Security Issue? Look Here!
http://forums.worldofwarcraft.com/thread.html?topicId=24702231244&sid=1

How he was compromised and you seem to be unaffected I couldn't say but don't take any chances and secure your system.