It’s a while ago that I was involved in these, but a managed move is a sixteen week programme with reviews involving both schools every two weeks and a formal review after eight. The child remains on roll at the original school until the end of the process. If successful, the child is enrolled at the new school. If unsuccessful, the child remains on roll at the original school and they should look at alternative arrangements.
Is there a short stay PRU that he might get a place at? I don’t know whether it’s still the case, but we were able to send children there for part of the week, whilst in school for the remainder. It’s supposed to be quite short term, maybe a term or half a term.
If he is permanently excluded, you can appeal the exclusion. If he is out of school, there is an obligation to provide work for him. The LA must seek to find another school for him, but it will be mainstream which is not what you want.
It’s difficult to see, without knowing the situation, what type of school you would think suitable, but it’s rare to get a special school placement of any type, and without an EHCP, not at all, I’d think.
Are there college courses he could access early with support from school? It does sound as though you feel the school has tried to be supportive, from what you’re saying.
It’s a minefield OP and I feel for you.