If he's an adult, I don't see the reason to say "kid" just to make it sound like we should sympathize with him based on his age.
Yes & no.
Depending on how long you've followed UConn MBB, you've heard Jim Calhoun and Dan Hurley both regularly refer to their college age student athletes as "kids."
That doesn't change the fact that the maker of the film might be sufficiently of age to be the defendant in a civil lawsuit, and he could be found guilty by a jury under a preponderance of the evidence ("more likely true than not") standard of harming the plaintiff, and ordered to pay money damages for such harm.
For all of this, the plaintiff would have to file suit, allege behavior that satisfies a number of specific elements that constitute the culpable behavior, and do so under procedural rules that would expose all parties to evidentiary discovery, including testimony under oath.
It's quite possible that a plaintiff would not want to expose himself to depositions, production of expense records, and other information that might inconvenience or embarrass him or affect interests he might prefer to keep private. And a Publix c trial would likely be less appealing for most.
It might be preferable to negotiate settlement terms that would include confidentiality agreements. Such agreements could conceivable apply to muting the voices of people engaged in behaviors that have been hinted at or claimed via innuendo.
It may be enough to have the X account shut down and the documentary made unavailable for viewing whether voluntarily or not.
I don't invite anyone who finds this subject of interest to do even a cursory search of "elements of defamation" and "defenses against defamation claims."