Sync to NAS or Dropbox

I have access to a friends Plex server so I can view his content. I am running my plex server on a QNAP NAS.
He has some video files that I want to take a copy of but when I try and sync the videos from his server to either my QNAP or Dropbox, the only device it gives me as an option is my iPhone.
Is it possible to sync these files to my NAS or Dropbox?

Both devices are listed in my “Devices” tab.

Cheers.

No it is not possible. PMS does not support giving someone a copy of your media because it is illegal in some countries.