Do you want him to directly upload to a directory accessible to your hosted domain or are you going to move the files and link to them?
There are two strategies you can take:
1. You can create an ftp account for him and then either create a symbolic link from somewhere in your directory structure or go in and copy the files to where they're supposed to go in your web directory.
2. You can set up a web uploader for him to use like uber uploader.
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