Keeping It In The Family (When It Sucks)

One of the reasons I don't share this blog with people IRL is that I dislike constantly arguing with people I see on a day-to-day basis. And constant confrontation gets both tiring and disheartening, especially with people you love or are otherwise fond of. I've had to hear "but she shouldn't wear..." rape-apologist crap from my partner, really awful racist jokes from my dad, annoying gay stereotypes from my brother, it goes on. And I usually express my dislike, but it's usually dismissed... I love my family, but the phrase "check your privelege" has never crossed their minds.

One of the most discouraging things is my mom, whom I love and who taught me the first things about being progressive and judging people around me by what they do and how they act, not what color or religion or orientation they are. The thing is, she was also my first example of "women don't talk about religion or politics" and "women shouldn't/don't speak up about ideas that are important to them, because it might creat a scene". She also showed me my first example of "women don't leave men who are verbally abusive to them (because it's not 'real' abuse)". That, however, is another long, bitter post.
My mom has a history of excusing the behavior of my brother and father and scolding me for actively calling them on their racism/sexism/chauvinism/whateverism.

And now I have a small problem. The story: While looking through my brother's digital camera to check the pics he took before he went away, we came across a video file. Shown is a girl friend of my brother's, let's call her E whom he's grown up with; we've both known her for ages. She's now 18. In the video, she's kissing another girl. Now, other than my not being comfy with my mom sitting there watching this also, this would not be a problem. Except.
1. Neither girl seems aware that my brother's filming them, although they know he's in the room.
2. Both girls seem quite drunk, which might be why they don't notice the camera. In terms of theoretical consent to film them, this is problematic. Underage drinking goes withouth saying. (I happen to know my brother was not drunk- he doesn't drink.)
3. (This is more philosophical on my part:) E identifies as straight. Since she did this in front of him, this video, to me, falls under the heading of "performative bisexuality" or "Hey dudez, watch this! Isn't it hawt when I make out with other girls in front of you??!?" See: Katy Perry.
-This has nothing to do with the wrongness of my brother making (and keeping) this video, it's just a pet peeve on my part.

No, the real problem is that my darling brother just filmed two (probably) drunk girls making out, in all likelihood without their permission. How is that ok? And can I use the word "exploited" to describe this, or is it too melodramatic?
...And my mom's reaction was bascially "Oh, isn't it amusing, he filmed the girls being stupid while drunk, drunk people are funny when you're sober". Also it was "Oh of course you have a problem with it, Lemur, you have a problem with everything."

And now, I'm faced with a problem. What I want to do is delete that video file. However, it's not my property, nor am I in it. Therefore it's not my decision to make, and I feel like to do so, however much that video bothers me, would be pretty friggin' arrogant.
So, do I leave it alone? Do I ask my brother? Do I ask E if she wants it, wants it deleted, doesn't care? Maybe she doesn't care. Maybe she knew she was being filmed. Maybe I'm overreacting.
But the fact is, none of that changes the fact that someone I know and love (not that I like him that much) is capable of this behavior, and the person who raised me is seemingly incapable of seeing how wrong it is.