My DS went through a patch of being an absolute turd. It was just painful to be around him, all day every single thing would turn into a hour long tantrum. I didn't want to be around him. If he was by some miracle playing nicely by himself I left him to it because even looking at him would create another tantrum.

What worked for us was a star chart. A sticker and a smartie every time he did something good, then a freddo frog at the end of every row (about 15 stars, so every 3-5 days). It was hard at first trying to find things to give the stars for, "WOW, I loved the way you put your rubbish in the bin" etc, an over enthusiastic response and a sticker on the chart. It slowly got easier to find things to praise him for and he started trying to earn the stars. We did it for about 4 months and then just phased it out because we seemed to be over the worst of it.

I am not sure if the chart helped substantially, but it sure did make a difference to my mental health to be on the look out for good behaviour and to reward it rather than just spending all day reacting to bad behaviour.

Good luck. I know it is hard, and harder with two on the go at the same time xx