help commands do not work

```
~/somefolder > which aws
aws: aliased to aws-mfa-secure session

~/somefolder > /usr/local/bin/aws s3 help

~/somefolder > aws s3 help

usage: aws [options] [ ...] [parameters]
To see help text, you can run:

aws help
aws help
aws help

aws: error: argument subcommand: Invalid choice, valid choices are:

topics | config-vars
return-codes | s3-config
s3-faq | ddb-expressions
```

Reproduce the reported behavior in the aws-mfa-secure CLI, comparing `aws s3 help` with `/usr/local/bin/aws s3 help` and checking how the `aws` alias is handled. Trace the command entry point responsible for forwarding help requests; done means help commands work through the tool without producing the shown invalid-subcommand error.

Written by the indexing model from the issue text.