Your account is your responsibility. If you have willingly given your brother access to your account, then you have also taken the responsibility of the consequences to your account on behalf of your brother.
Were you aware of your brother's use of X-ray? If so, why did you not report the incident to any staff members? The rules have explicitly stated that the use of X-ray is strictly forbidden on the server. Furthermore, referring to the ban appeal format:
2. Use effort: Moderators want to unban you, but not unless you actually put some effort into trying to get unbanned. Write a detailed appeal explaining what you did wrong, why it was wrong, and what you should've done instead. Make us want to unban you. One or two sentences/no apology makes us want to deny your appeal.