Your lawyers are trying to fill you up with something other than accurate facts.
From what I am given to understand, your brothers application will be processed in the same manner as every other family application is processed.
As Rob told you, it will be up to CIC to decide where to send the application. It usually really depends on where your brother currently is. If he is here in Canada with you, they may opt to complete his application in Ottawa because he is here. I wouldn't bank on anything though until the application is finally sent the processing office.
I am not sure why you would also need to file for H&C. Your brother being the last 'family' member for you is all you need to file successfully. I guess that is your lawyers way of making some more money off you or something, I dunno *shrugs*
Anyway, best of luck to you.