This is why it's important for the black family structure and/or the community to be intact. If you don't come from a good family which many of us don't, at least have some good people you can call on who can assist in cases like this.
If his mother didn't show up it could have turned out way worse (because let's face it, bodycams don't mean shyt) and they would have fukked with him even more. It's also important to teach your kids the law and to stress to them that they need to keep a cool head at all times no matter what provocation they face. I'm glad the mother didn't do any screaming and flailing of the arms and that the kid was calm and didn't take the bait.
It's the same over here, the police may not be as murderous and psychotic, but they come with that same condescending and passive aggressive tone assuming you're ignorant and ask dumb questions and make stupid remarks to piss you off, hoping you'll lose your cool. I've seen too many black folks fall for it over the years.
The best way to handle them is how a chick treats an annoying dude trying to chat her up - one word answers, saying as little as possible and ignoring the insults.