Am I the only one who has no idea who this lady is? Either way, the person who posted this video is clearly race baiting.
I've been the FO on flights with pax issues and I've never see it so bad that a Captain had to go to the back and deal with it directly. If he was back there, I'm inclined to believe that she was not listening to the FAs. I have however been in the back as a pax, before I was an airline pilot, where someone was causing a scene with the FAs. Then when the Captain came back was all compliant and saying she did nothing wrong, etc... To be honest, we were all hoping he'd toss her off. Phone cameras weren't a big thing yet.
Then again, there is nothing in this video that is even remotely close to a fireable offense.

I love this! But what if she had left him hanging...then it's just awkward and then he'd be accused of being even further "uncool."
This is like doing flybys, especially big primetime events, in the AF. AT BEST, you did your job correctly, hit the TOT and noone says a thing. At worst you lose your wings. The "in between" is missing the TOT because ATC calls out a random bug smasher, or the band plays at half speed, the singer sings 2x faster than stated, both started late, etc.... Zero sum game! Just be the ground guy, take pictures with the cheerleaders, stand on the sidelines and take all the glory.
Your last sentence says it all....your family knows how to act in public, thus wouldn't be in this situation. For a Captain to come back and talk to her leads me to believe that she does not. If someone is acting like a child then speak to them like one, if they're acting like an adult he likely wouldn't be back there.