are you pissed off because he was being disabled? You probably need to find out a bit more about asd and occupational therapy to help him as it seems that you don't know some of the important stuff yet. and are interpretting things through a NT viewpoint and probably trying to parent a nd child like a nt child
sounds like he was having a meltdown. once this has started, no he can not help it, he probably can not remember anything that happened in the meltdown as he will not have been able to make new memories because the part of the brain that makes memories was not working at that point and he was only using the emotional "old brain" at that point. (it's how the neurodevelopment team described it) effectively you are asking him to apologise for something he has no memory of.
If you want sympathy as a parent you are best off in the goose and carrot pub on sen chat. It's a good place to let off steam. virtual gin on tap by the barrel load. here, not so much as it is for ND posters rather than parents of autistic kids. quite a few of us are going to see it from your childs point of view and have more sympathy for him. The goose and carrot has the advantage that your posts are deleted after ninety days.
So meltdowns happen when he is overwhelmed. This may be due to all sorts of reasons. could be sensory, or upset over having lost something, someone has moved his stuff, or his routine is out of whack or bloody school, or you have been a bit of a numpty regarding autism . You need to be responsible to help him regulate his emotions. Best way is prevention as once they have started, there is not much you can do to stop them. You need to be aware of his triggers and do your best to avoid them.
some sensory stuff is actually physically painful. some sounds cause pain in my ears, for example. actual physical pain. maybe some sensory stuff is reaally painful for him. his sensory profile is going to be unique to him. he may be over or under sensitive. so light touch is often painful, or clothes irritating, or he needs to lean on stuff and do lots of jumping or he is senstive to sounds and lights or seeks out loud sounds, or will not eat stuff because of texture or make sensory seek strong tasting foods or like chewing stuff. etc, etc etc.
stuff. some autistic people are very attached to their stuff. don't touch it, don't borrow it, don't move it. fucking about with it can trigger a meltdown.
some things seem fucking random. (eg it was really important to have a dirty plate removed NOW, earlier this week, and yes, I was not as sympathetic to that need as I should have been...because as it happened I was a bit meltdowny myself at that point. it was moved but not quite as urgently as the noise eminating from above suggested it should have been... ) from the op I suspect that it was something that seemed randonm to you that triggered the meltdown, and he did not have the words to express what it was, you were not in the right frame of mind to listen carefully and process that... (because we are all human and somethines we just want to watch the fucking film or not walk up the stairs twice in my case of the dirty plate)
Prevention:
keep blood sugar levels up. first sign of dysregulation feed them. better to feed regularly annd avoid the dysregulation in the first place.
ditto drinks, and correct temperature, as he may need you to tell him to take layers off or put layers on as it is common not to be able to recognise being to hot/cold or hunger or thirst for that matter. (interoception is fucked... may be noticable in not knowing he needs to go to the loo until the last minute.)
work out his sensory profile and adjust his environment to suit. (look it up)
work out his triggers. what happened this time to set him off... make a note, of everything that happened and see if you can start to spot patterns. make adjustments to suit.
don't try to do too much. one thing per day and some rest days at home might be required. work out maximum length of time you can do stuff and don't go over it. just five more minutes might be disasterous. (been there done that, got the scars to prove it) ( you migh need to tag team to do stuff with the other kids)
adjust your thinking. you are parenting a disabled child. you have to parent differently to nt children. this is really difficult to adjust to as the whole world seems to be about you should be doing this or that.... I think this is one of the hardest things to do and it is really easy to fall into the trap of trying to be a nt family when you are not. the equivalent of trying to take your kid in a wheelchair on an obstacle course made for NT athletic kids. just you are not going to be able to push a wheel chair across a rope bridge, you are not going ot be able to do stuff in the same way, with a ND child that you would do with a NT child. But it is harder to see this and accept this as we want our kids to be able to do all the stuff others can. They will do stuff, but in their own way and at their own time and you can work towards doing stuff but at their pace and it might not be the same stuff. and it is really hard to get your head round.
occupational therapy... every day you can manage. calming activities. ask for a referral and google in the mean time. OT thought that one activity every day was important.
try to intervene with calming activities, or quiet if you spot the dysregulation first.
screen time might help.
I can diffuse early meltdown phase with glucose, and sometimes tickling and humour works, if early enough. helps you too.
help him to breathe slowly... using star breathing or some other technique. you do it too. try blowing bubbles, or getting him to blow bubbles. the breathing thing helps. You need to be calm too as your irritation will be like pouring water onto a chip pan fire. even normal talking may be perceived as being cross. try a singsongy voice.
During a melt down: (they can vary in intensity)
don't talk. he can not process it. it will make it worse.
if he is telling you he is upset over something, agree that it is upsettting for him, even if you are not bothered by that thing personally.
try hugging firmly.
try rocking back and forth in one direction.
try putting him somewhere quiet and safe
ie find what works for him
Do not attempt to talk to him about what ever it was for well over half an hour or so after things appear to be calm. adrenaline takes a while to get out the system. you need it to clear compeltely otherwise you could set the whole thigng off again. even if he appears calm he may not be yet.
as a previous poster has mentioned, try the what could we do differently approach.
look after you too. You are going to get an adrenaline rush from a meltdown and then a crash as it wears off. you need time for it to clear. (mine manifests as sudden onset of feeling really weepy about half an hour after the end of their meltdown) look after the other kids. you all need time to recover.
he will get better at controlling meltdowns himself, in time, you need to teach him techniques in the mean time, firstly be doing it for him, then teaching him to recognise the signs. He will still have them but they will become less frequent, more preventable and more controllable, even if he still does have some humdingers. You need to work with him to allow him to withdraw, or go and calm down or avoid stuff that triggers them and adjust to the limits of his ability. breach those preventative measures and you are in for trouble... (it is sometimes really easy to push the just one more... with resulting meltdown )