One thing I can speak to from experience - I cared for a boy/young man with autism, who could be very volatile. His parents learned over the years how to avoid the outbursts at home, danced a very careful dance around him, and declared themselves successful.
No demands were ever placed on him, in essence, he controlled the house - not through deliberate means, but because his parents were afraid of what he was capable of (by the time he was 16 years old, he was 6'5", and his father had trained with him in martial arts for many years - with the young man eventually earning a black belt).
Finally, they asked me (after not being an active part of their family for some time) to spend an evening with him so they could celebrate their wedding anniversary.
I served the evening meal his mother had prepared, but put it on the plate the "wrong way". I used the wrong glass for his drink. I asked him if he wanted to prepare the rest of his dinner the way that was right for him so he could show me how he preferred it, and that was the straw that broke the camel's back.
Because, over the years, he had not learned how to anticipate the red mist, and definitely not learned how to avoid it or try and back away from the edge - it did not end well. I was hospitalised, he was institutionalised.
I am not saying that this will happen to you, I am saying that this is an extreme example. Because of this, we push my DS just a bit - in very controlled situations, we help him to learn his triggers, and how to back away. He has not had a meltdown in some years now, but we are always aware that it is possible. We see the importance of making sure that he can find his control, since we know as he gets older we will not always be there to recognize and defuse a situation.
I am sorry you are going through this - it is so scary, trying to protect your other children and yourselves, trying to help your DC find his centre as he is feeling just as scared and out of control as the rest of you, trying not to lose it and make things escalate.
Honks 