AIBU to not have a clue how to help?

[AutismKidHelp]

Obligatory change of username to protect the innocent, but I have been here a long time (penis beaker, the mad woman who took over the house etc)
To the question. My DS has autism, and is really struggling now he is in year 6.
Hes done his mock SATs exams, but despite getting “expected” for everything, he has no self esteem and doesn’t believe he can do anything. He is also incredibly angry all the time, acting horrible towards everyone else in the house. I recognise he is burnt out as this term has been super long, but he’s now refusing to do anything in class. He has a 1-2 support for certain lessons and classes which he needs that extra help in, but doesn’t get on with his regular teacher. He has now refused to do anything for his support worker.
I don’t know what to do, as he is really volatile, the mere mention of school is enough to set off a screaming/crying fit and apparently he had a 20 min crying session in school today.
I don’t know how to help him at this point. We have an EHCP in the works, I’ve fought with school to get him a support teacher, I’ve argued and advocated for him at every turn, but he’s just stopped co operating. I have pushed to get him melatonin at night time, I’ve fought for him to have his special “support person” in his exams with him, to get him to not do the auxiliary tests that come with SATs and I’ve basically done everything I can think of to help him, but like I said, he’s refusing to participate in class, he’s sat crying rather than learning and he just doesn’t do anything.
I don’t know what else to do. Our communication with school is dreadful and they are refusing any more help. I don’t know what else I can do to help him!

Will he be on Easter holidays soon? The break may really help. Does he have a safe space in school he can access to regulate? Some schools have a sensory room or nuture room, he may benefit from some time alone to regulate when he is struggling.
Some therapy may help to, my DD had support from Barnados. They may not have the contract for your area but the school nurse and possibly school SENCO will know where to refer for this support. My DD was really anxious going into school and unable to focus, she started self-harming. The therapy really helped with her self-esteem and coping strategies.

Yes he’s going on Easter Holidays on Friday. We are actually going away over Easter, to try giving him a mental break from being in our village and around school/people from school etc.
There is no dedicated safe space at school, and he is just taken out of class. We can’t really talk to school about it again because they quite literally don’t want to know.
Therapy is a good shout out, and if there’s any available for him in our area, I will certainly look at it. The SENDCO refuses to speak to me or DH so she won’t be useful, but I could probably google and look into it myself. I didn’t know Barnardos even gave us an option, so that’s helpful too, thank you.

I think you should consider moving school or looking at a specialist setting. If the relationship with school has broken down it seems pretty difficult to make more changes