My first instinct is to say: bad idea. So I'll say it. But here's why:
I think your H will get frustrated when he asks and people don't want to be videotaped. I think he will be frustrated if they do, but then later change their minds about it. In other words, I think his expectations are set pretty high.
But lastly, even if this videotape is shown those who you want to expose, they won't get it. So again, your expectation will not have been met and you'll feel a whole lot worse. Also, later it could be used against you two. In other words, if someone in the family has a change of heart they could say "they manipulated me to make that tape." Then you look like the controlling one.
I think it's better to keep the line of communication open with others who feel the same way. But let them pick their time and place to "expose" if they want.
Maybe I'm thinking of those Ethics training videos they show at work, but one thing that keeps popping into my head is that just because you've been wronged, the best thing for You may not necessarily be to become the Whistle Blower. Remember to take care of You. The last thing you want to do is make it worse for yourself. So you expose the bad guys. Does do you much good if in the process you destroy your mental health, lose your job and a healthy relationship with your H. No what I mean? Not saying that terrible things Would happen, just saying, ask yourself if you could deal with it if the worst did happen and everything backfired and it all just blew up in your face.
There are no imperfect intentions, only imperect plans.
