Afraid transition from junior to secondary is where the gap tends to widen and show up difference and ability or not to fit in with systems and others further. Mine went to secondary considered coping at school, and very quickly stopped coping.
(Having said that, junior school had just expected less and less out of him in terms of education or participation, and the LEA didn't think him slowly sinking was a bigger deal as I did.)
I'm out of date as my knowledge is statements (of SEN) rather than EHCP's, certainly then social needs were only important if they were affecting educational ones. In our case they were, as it was a jungle, and he was instant prey.
However I believe EHCP’s were supposed to change that situation.
I hope I'm not being too negative here, but have you understood major differences in school structure at your secondary? A lot may be dependent on how large and urban the school is. Someone from a better school than ours assures you they would manage those things with your child. Our old school still assures parents, the children will manage. (They don't, there's a v.high drop out rate from there for children with ASD.)
He’s no longer going to have the same group of peers (who are used to him/supportive or at least leave him alone etc) for most things.
He will be in a different classroom possibly with different kids, every 50 mins, having navigated crowded, possibly loud, corridors to get there. So will he be lesson/learning ready?
What is he like with trips, sudden team building activities, and bearing in mind Covid, outdoor activities? Sometimes they happen on week 1 and can define relationships for the future. PE? Changing for it?
Very quickly the need to fit/be the same strikes in secondary.
Isn’t he a couple of weeks away from knowing his future school? If so I’d be knocking hard on secondary SENCO’s door right now, asking do you want this to be a successful transition, or a lot of work fixing it later?
One thing to ask for anyway, is to visit the school and know its layout in advance. (may need covid test 1st) Normally that would be Ok, and it can sometimes show up issues.
He should arrive with every staff member knowing about him, and that he's not being intentionally 'rude/sullen' etc in his staring or silences.
Right now he's not a school refuser, everyone wants it to stay that way.
If he’s highly literal I'd assume he's going to need lots of help decoding several lessons, (and unless he’s lucky with his peer group) otherwise alone he’ll swiftly be drawing negative attention from others as well as struggling.
You might want to consider writing your ideal scenario 'statement', and then working backwards, as to how reasonable it would be and ensuring it's helping him to independence, not smothering.
I started with a requirement of: Significant differentiation to meaningfully engage with the school day and educational syllabus. and went on to show what that was, what it would look like and why it was needed.
The 'school day' matters, and soon affects learning. Schools may not like to advertise it, but part of what they do is to prepare for the workplace.
I’d look at long term educational outcomes if he’s masking at school and blowing at home. Is that sustainable?
There will be elements of the curriculum that will be about being a functioning member of society, so that’s part of modern education, right? Education, especially for those with ASD, isn’t just about syllabus and exams, he has to be able to apply that education into adult life.
When looking for provision I suspect SMART is still a useful acronym:
Sustainable
Measurable
Attainable
Relevant
Time Based
So much of what was offered us (things that didn't cost time or money mainly) could be instantly seen as below par as they didn't meet two or more of those objectives.
Somewhere down the line the ability to take home work and do it, is surely going to become an essential skill for him. I may be wrong but suspect that one is likely to become your problem. (why I include ours.)
The homework issue we had was inability to record and understand what was required to be done, how much, and by when, in the time given in the lesson, from the whiteboard, so I sought preferably a pre printed slip with details, or less preferably for all, it to be written by an adult into his communication book. That meant it could fall to me to help work out what they actually wanted leading to a major reduction in the amount of work over literal poor child believed was expected of them. Is the school using any sort of parent portal?
Transitioning between lessons is likely to throw up issues from what your describing. Is he able to get everything in and out of a bag in a timely manner? Poor executive function floored mine.
A male mentor might well be an asset if the school has them, even if he is silent with them. It also gives him another place to go or be sent, if things are getting difficult, and another voice in reports. (Might sound strange, but ours was great in openly saying he could do nothing for Dc unlike with most of the kids he mentored)
Sorry this is so long, but I hope there's useful stuff in it somewhere.