I'm at a loss as to how to get this to sink in with DH. He seems to run along the same lines as DS2 sometimes, I swear! 
He expects things to be done a certain way, and trying to get him to "think outside the box" or approach things from a different angle or in a different order just frustrates him.
I can't even begin to count the times he and DS2 have a ridiculous power struggle over something that is essentially SO unimportant that I can't believe they're fussing back and forth over it. This morning it was brushing DS2's teeth AFTER he put his uniform on (which is how I normally do it). DH wanted to do it BEFORE he put his uniform on, so he didn't get toothpaste on the uniform. A good thought, honestly, but to DS2's mind it's backwards, as that's not how it's normally done. So DS2 is screaming, DH thinks DS2 is fighting about not wanting to brush his teeth at all, and I'm sitting here going .
Is it just in our household, or is the father slightly more "out of touch" with the fine details of ASD issues and such. I think that partly because I'm the one doing the majority of care, doing the research, going to appointments, dealing with extra stuff (SALT, OT, and so forth), that I most likely have a better understanding of what he wants when he is kicking off than DH does. I also think partially that DH just hears the kicking off and fussing and just assumes it's this or that, without stopping to think about what led up to it or actually listening to what he is saying.
Sometimes DH can be quite good about it, but I also think that occasionally because DS2 can mimic or copy phrases and sentences and use them (sometimes appropriately and sometimes not) in conversation, that DH thinks DS2 understands more than he actually does. I am constantly reminding DH "he's FOUR" and "he doesn't understand what you're saying" or "you need to break it down into terms that he can follow and remember" or "don't run all the information off to him at once, he won't remember it - bit by bit please."
I know part of it is DH's depression (which he is on meds for), and that he is not so great at remembering the finer details. But as I am dealing with an incredible amount of stress myself, plus shouldering a bulk of the responsibility at home, I find it very frustrating to have to keep reminding him how to deal with DS2.
sigh... please tell me it's not just us....