I understand your frustration and fear OP.
I removed my child at the start of yr3. I then home educated her for almost 2 years, whilst we got her diagnosed, an EHCP and tried to undo the damage caused by being in an inappropriate environment.
I took two years (unpaid) family leave from my job and she returned to school (Yr5) last September because she wanted to be part of a school community and financially we needed me to work again. It was both the hardest and most rewarding two years I have spent. She has no specific learning needs, in fact she has an extremely high IQ identified as part of the EHCP process. But she was incapable of demonstrating her abilities in a mainstream school environment.
Our initial plan was to return to mainstream, but frankly we were appalled on how bad the situation had got in terms of lack of funds, junior class sizes well above 30, tick box mentality focus on doing things to meet OFSTED requirements as opposed to children’s needs, high teacher burnout/turnover and the reduction in the number of available classroom support. We visited over 15 primary schools and met some fabulous and not so fabulous SENCOs, but even with a funded EHCP, they either didn’t want her or we didn’t want them. Independent specialist schools would have meant boarding and moving is not an option for us.
Someone in the home ed group we went too mentioned the special school she is now in. I had ruled it out due to her academic abilities, but I did go to visit it. I cried all the way home, because I knew I had to let go of my beliefs about mainstream and integration and because I realised that for the first time in a long time I was in an educational environment where her needs mattered to them and where teachers understood the reasons behind the behaviour and how to deal with them in a positive manner.
It is not totally without its problems, but it is a million times better than before. She is beginning to develop social and emotional skills and above anything she feels wanted there. Is she having her academic needs met fully there?, no. But we are focusing on the now and we fill her non school time with learning opportunities.
Does she copy some of the behaviours she sees, yes sometimes she does but she is also learning what is appropriate and how to regulate better. She also is now more able to interact with NT children she meets in out of school sport and music activity clubs. Before, when she was in her primary school, she so was so stressed in clubs she could not cope with them (or them with her behaviour). But she wants to go to them now because she is being taught about how to function in a group environment.
My child's brain is wired differently and that means she needs to be taught differently too. She needs to be taught explicitly things that typically developing children learn by osmosis. These are things that mainstream generally don’t ‘teach’, such as how to form and keep friends, how to communicate socially, how to understand the difference between playful teasing and bullying, how to understand other people’s feelings and views, how to work in a group situation and how to be part of a wider society.
I had to learn to lean in and see my child. As a family we are beginning to find peace again. I hope you find your peace OP.