That sounds like how I was as a child. And I now know I got very angry and screamed a lot because I’d feel like people were against me for some reason, and that nobody was listening to me, so I’d lash out. Then I’d realise what I’d done later on after I calmed down a bit so I’d start being nice to my parents and saying sorry because I really didn’t mean to hurt anyone. I remember I used to scream things like ‘I hate you’ to my parents when they tried to make me do something I didn’t want to do. But I definitely did NOT mean that, I was just very overwhelmed and felt like nobody was on my side.
As for the lying, I used to lie because I felt anxious that people wouldn’t understand my true reasons for doing things. But that can be different for every child.
I think in my case it could have been something like mild Oppositional Defiance/meltdown but I never got any official diagnosis for that – it was just always considered an additional aspect of ADHD to my parents. It got better as I got older (medication helped me calm down also) and I realised what had been going on in my head, so I was eventually able to discuss it openly with my parents and apologise properly.
So yeah from my perspective, it just sounds like he doesn’t know how to cope with the intense overwhelming emotions (because he’s still a kid and hasn’t worked it out yet). So it helps to be as patient and understanding as possible (though I know it can be hard in the moment). It’s hard for me to give advice from a parent perspective but I thought it might help to know perspective of a child (now young adult) who was this way once.
I definitely recommend practicing self care when you get the chance, because I wish my mum had done the same for herself more when I was being difficult.