V good advice from @Secretsquirels
I have two children who behave as you describe. Both diagnosed with a range of ND, one with an EHCP in specialist school.
In addition to what @Secretsquirels said, I'll also tell you what has helped us;
ADHD medication for one child.
Anti depressants for me and my dh.
Filming a violent outburst and sharing it with our child's TA, SENCo and head teacher. It was about 10 days after said outburst and my child behaviour one morning just broke me and had me in tears. I shared the video with these members of staff and it got the ball rolling.....we got Early Help support and given a place on an NVR (non violent resistance) course where the leaders were ND and trauma informed. This has been helpful.
I have counselling.
DLA, carers allowance and a significant shift in how our family life works.
Therapeutic in put....in our case as speech and language lady who wofks with our child weekly, as part of their EHCP.
Apply for an EHCP and appeal if it gets turned down.
And, for a PP wjo said violence is not a factor of ADHD...no it isnt BUT impulsivity and emotional dysregulation ARE. When coupled with a child who doesn't have typical social and communication skills it is not a surprise that for SOME AuDHD children their presentation has a level of violence.
It's absolutely soul destroying OP. I'm in it with you. If you DM me I can point 6ou to some helpful resources. I'll outline a few here:
Sunshine Support-useful webinars and advocacy.
SEND parenting podcast.
Sarah Fisher Connective Parenting.