First of all how long did they suspend you for? It should tell you how long on the email notice that they sent you. It could be just a 7 day, 30 day or even a permanent suspension..
you need to find out how long you are suspended for. Look back at the email and it will tell you on there...
Where you messed up was letting your brother link to your account. Alot of sellers have multiple accounts. All you need for a multiple account is a different email address and you are allowed to keep all the rest of your info the same,(credit cards, contact info, address, etc.) And the trouble with this is that if they suspend one of your accounts, then all the accounts associated with the others gets suspended as they deem all the associated accounts as being the same person....
Evidently since you let your account be linked to your brothers, they associated yours with his and when he got suspended they considered you account and his as being the same person since the accounts were linked.....
You should never do that. And you will have to ride out the suspension until it's lifted and your account is re-instated. However it could be a permanent suspension and you will not get back on.
If this is the case then you will have to open another account completely using a different name, credit cards, addresses, ip adress (computer address) and the whole ball of wax...If they see anything associated with your old info they will not accept the new account or if it does happen to slip past them, the system will catch it and suspend the new account...
Safest way to go is to sign up for a new account using your wifes, or girlfriends name and a completely new credit card (that means it cant be yours) a new IP address for the computer that you use and all new information for anything else that is required for the new account....Ebay mostly tracks users by the ip address of your computer. (an IP address is basically just like a house address, it is unique to your computer). But it can be changed.
But the above is a last resort. I would first find out how long you are suspended for and then decide what you need to do..There are services on the internet that will set up new accounts for yu including new feedback to get you started....