First, no matter what means are used, children should first know the consequences of making this mistake again. I don't know if this method is right or not, but this child obviously has a little crooked outlook on life and shows great disrespect to his elders. According to his attitude, this attitude should not exist for a day or two. It is estimated that he treats his grandmother like this every day, and it is useless to persuade him. In that case, he can only be like the ancients, "a dutiful son is born under the stick" and be beaten first.
Beating him is not to make him succumb to this matter physically, but to impress him ideologically. As long as he treats his elders like this, the result will be a good beating. Even if he wants to be rude to his elders, he will think about it first. It's not too late to reason with him slowly when he calms down. Now we must suppress his arrogance.
Second, the child's attitude towards grandma is so bad that it is estimated that parents are at home, and education is useless. This is definitely not a fabrication. A family, especially a family that runs in the family, children can see the atmosphere of a family best. The child was born with a blank sheet of paper. He imitates what his parents teach him to learn, and he is so disrespectful to his grandmother. That means his mother or his father has a bad attitude towards grandma at home, otherwise he wouldn't dare to talk to grandma so blatantly.
However, whenever someone in the family respects his grandmother, he doesn't dare to do so because he knows that the consequence of doing so is to offend the whole family. He is a helpless child, afraid to challenge the bottom line of adults, so is it useful to teach him? What's the use of parents educating a child like this?
Finally: If this is my son, I will give him two big slaps when I see this video and go home. I'm not allowed to have dinner, let alone breakfast. Now I dare to do this to my grandmother, and I am still not sure about my mother in the future! Dare to talk to your elders like this and spoil them!