Melj I'm also still waiting for all the people on this thread who have said the child should just keep saying "No thank you" ad nauseum to quantify the number of times you have to say it before you are allowed to get frustrated that you are being ignored, and whether or not that number is different based on whether it's two adults talking or an adult and a child
Until it becomes absurd and the granny stops. And there is nothing wrong with saying, 'Please - stop badgering me', or, 'Please let's stop this,' if she keeps on with the badgering. A child can name what is going on without shouting or accusing.
The feeling that you have to slam a glass on the table to put a stop to it comes from panic that something is going to happen that you don't want unless you take drastic action, plus a buildup of frustration that is avoidable. There is no need for that panic. This was a relatively minor scene that played out, not a fight or flight situation where there was an adversary armed with a bat demanding lunch money.
The child is allowed to get frustrated. Nobody expects an automaton. He should be equipped with the skills to help him retain control, avoid panic, and assert himself. You can be frustrated and still keep your head and come out on top.
It is a problem that the only responses the child had were good manners or going nuclear. There is a middle ground where the child ups his communication game. He needs to be taught to seize that territory.
Hetero
it's absolutely a great idea for the OP to work on these strategies with her ds now. But he's bloody 10 (you only need to go on the retail workers' threads on here to see how many grown adults lose it completely on a seemingly regular basis) and was being pushed probably beyond any pushing he's experienced before. Maybe he actually held out longer before his rather minor explosion than he has done in the past?
Those adults shouldn't be losing it on a regular basis. Something is not right there.
A parent really has to recognise that there is an issue when a child 'explodes a bit when pushed'.
The child's anxiety must be addressed. He needs to be given tools to recognise his own emotions and he needs rehearsal of appropriate phrases. He needs assurance that everyone feels upset/frustrated/annoyed/angry/panicky, and encouragement not to allow those feelings to overwhelm him.
He also needs an atmosphere at home where it's ok to make mistakes, one where there is give and take and negotiation where he sees people modeling stepping back and focusing on results where everyone benefits, one where everyone gets a bit of fun poked at them and everyone still stays friends.
He needs parents who are willing to sit him down and talk through responses on his part and to reveal their own responses to situations they encounter. He needs to see patient responses modeled. He needs to see his parents playing the long game, accepting that situations are beyond their control so they are going to shrug them off (by not commenting on others' driving, barging in queues, etc).
Maybe the parents are a bit inclined to panic themselves? Mutter about other drivers, curse at people who have parked badly, rant about people being careless or rude, or gossip critically about others?
The general atmosphere at home and the attitude towards mistakes of others and of the child can often have a lot to do with a child's tendency to jump off the deep end. It's a good thing to assess whether parents are giving the impression that lots of little things are the end of the world, and to try instead to not sweat the small stuff.