Ugh the emotions this evokes.....
This kid makes me angry. Yes, he's a kid. Yes being patient is perhaps the biggest challenge as a kid, but he needs to be shown, very firmly, this is NOT how you treat your Mom. NOT EVEN CLOSE.
I feel for this Mom and parents in this situation. It's easy to sit back and judge while watching this video. Who knows the situation. It appears she has another child on her right. Maybe you take them into a bathroom, isolate and discipline? Overall, she looks like a pretty patient Mom although it might be time to dig in a bit against this kid. Otherwise, it could be a long haul. Either way, this isn't easy. I do applaud her patience though.
One thing that concerns me is the reaction of the little girl on Mom's right. Kind of just looks like she thinks this is normal, right? Or perhaps she just doesn't know how to react.