Kindly, OP, I think it is because you are being a little obtuse, if that's the right word, about what your DS is actually doing. Can you not just say:
DS is completing his EPQ , the theme of which is ..... To do this he needs to make a film which shows... the research he has done is about....
To give an example
DS2's EPQ was an exploration of racism in cricket, motivated by recent news stories and wanting to extend his sociological and historical studies into the contemporary world of sport. To do this he read various academic and biographical texts from different cricketing countries and periods and watched various webinars and followed the news, maintaining a log of reflections. His artefact was an academic essay and a presentation to peers on the ECB scandal.
or
A student elected to write and self publish a novella. She researched the novella form and conducted historical research into witchcraft. She complied five drafts and investigated self publishing and commissioned book cover art. She presented the various drafts and reflections to an audience [please not this student is now doing English at Oxford -so extreme!]
Then we might understand how the film fits in with what is being assessed and be able to see how far the quality of filmmaking matters. It genuinely must be frustrating that the media departments are being less than helpful - I'd get him to ask his tutor for help in convincing them to borrow equipment.
I do think EPQs are so much simpler when they just write an essay/do a presentation!