Different perspective here but hopefully I can give you some insight.
I'm diagnosed as AS, as is my younger brother, (two older unaffected siblings) and we were brought up for the most part by our mum as we have different fathers who were never really involved to that extent.
I can tell you OP just how difficult my own mother found it looking after the SEN side of things by herself, with other children to consider, and how it was really obvious to us that she was struggling from it at times, balancing the therapies and meetings and all that other stuff.
Your husband is being unreasonable in leaving it all to you, as I've seen how that can wear someone down week after week, and I imagine if he could be more involved it would take a load of your shoulders. As your children age there is the worry that they will notice and could misconstrue that they are the cause of your unhappiness, rather than your husband's lack of support
You say he parents them as if they aren't disabled, something that can be incredibly difficult for ADHD/AS children to deal with, although you haven't given examples I assume you mean it's not always at the forefront of his mind when he interacts with them? Our oldest sister struggled immensely with the diagnosis of my brother and would often cause him to have meltdowns and tantrums because she refused to accommodate towards his needs.
He is just as responsible as you are for your children, all the time. Even if his primary role is to go to work, and you are the sahp, you both have the same duties to your vulnerable children and imo I can't see how just because he has a job, he can't help you in the evenings or be involved. 