You can specify the 'formatter_class' when creating each subparser:

    sp1=sp.add_parser('cmd1', formatter_class = argparse.RawDescriptionHelpFormatter)

The 'add_parser' command is the one that passes a variety of **kwargs to 'ArgumentParser' (or what ever parser creator is being used for the subparsers).  'add_subparsers' is more like a 'add_argument' command, creating a '_SubParsersAction' instance.

Few, if any, attributes of the main parser are propagated to the subparsers.  I'd have to study the code more closely, but I think it's just the parser class that is propagated.