TheLadyEvenstar, why are you doing this, again? Why are you posting in AIBU about your DS1, when you know exactly what will happen?
You know that your DS1 has behavioural issues. You know that he needs (and is starting to get) serious help with his past and his current issues.
Why on earth did you allow your DS1 to wind your DS2 up for 30 minutes? Why did you wait until he disobeyed you 5 or 6 times before you gave him a consequence?
You are going to have much bigger problems than you have now if you don't start taking it seriously. Your postings always have a level of humour about them, like you think that your DS1's behaviour is on some level amusing. It isn't. It is sad and shocking.
Your DS2 is going to learn most from what he sees. What he is seeing is that you have no control over DS1, and that you won't protect him against his brother.
I get challenging behaviour. I do. My DD1 can be absolutely determined to wreak havoc when her younger sisters are playing nicely (she has SN). BUT my job as her parent, and their parent, is to be that protection. So, hard as it is, I do whatever it takes to protect them from the menace that is my DD1 when she has that agenda.
My DD1 is only 4.7, but she is determined, resourceful, strong and unbelievably stubborn. My job as her mother is to show her (regardless of how I feel) that I am More Determined, More Resourceful, Stronger, and More Stubborn. If she gets a whiff of being able to overrule me, it will be game over. So I win. Every time. If all else fails, I put her booster chair onto a dining room chair, then strap her in it, in the hallway for 4 minutes. It might take me half-an-hour to get her into the chair, but once she is there, it gives the littlies 4 minutes of calm.
You have to accept that he is not going to like not getting his own way. It isn't a sign that he can't do it. It isn't a sign that you've lost. It is a sign that finally you are taking control.
Do you know what? The dishwasher thing? I would have said "Please do the dishwasher". He screams, he cries he wishes you were dead? "I'm sorry to hear that. Dishwasher, please." So what if he wishes you were dead? He is a child. He is just saying whatever he thinks will avoid doing the dishwasher. I wouldn't care if my child spat vile abuse at me for an hour, they'd still do the dishwasher, and then they'd get their punishment for the way they treated me later.