I hope you have done the things suggested when you posted on these subjects a week or two ago.
I think you must - as well as doing what was suggested - take this up with your brother. There seems to be no rational explanation of why he has done this so you are right to be concerned. The danger is obvious - the account is in your name so you could be chased for any unpaid bills and have a lot of hassle sorting it out.
As well as talking to him, you should ask the Credit Reference Agencies for your file at the address he has used - and at any other addresses you think he might have used. You can only ask for records in your name. Anything that comes up will relate to bank accounts, loans, credit cards etc., but not to utility bills. You may have to explain to them that you want this information because you are concerned that your name may have been mis-used at the addresses.