Recipient of my shared folder is getting a "storage full" error

Hello all,

I suspect I know the answer to this after reading through some related posts, but there was none with this specific setup, so before I devise a complicated workaround I wanted to check in with y'all.

I'm starting a new podcast project, and I created a folder for audio files. I have 2TB of storage and only use about half of it at this point.

I shared my folder with my cohost, since he is going to be editing the show.  We are in different parts of the country so are using my Dropbox to me to send him my audio. He puts our two sides of the conversation together, and then posts the finished podcast.

After only three episodes, he is getting a "storage full" error, even though the folder is not originally his. 

Question: Am I correct in saying that because I've shared the folder with him and given him read and write access, that the folder counts towards his storage cap? And will it NOT count against him if he only has read access?

Question followup: If that is the case, the simplest workaround I can think of is to create a second unshared folder that only lives on my computer, and I just drag finished episodes into there, which should move them out of our shared folder and free up the space for him.  OR, I make the main folder read-only for him, but set up a file request folder that he can upload files to, but that seems pretty cumbersome.

Thoughts?

Thank you!
~Travis