I think we may have had a tiny breakthrough with my stepmom today. She accepts that there is something not NT with my son, but has maintained that much of his behavior is related to laziness. Now, in all fairness, he does quite enjoy avoiding things he doesn't like such as chores. Not that he isn't capable of doing the chores, just that he'd rather be doing something fun like playing with Legos (which I've heard is a pretty common thing with kids his age, and heck with adults, too. I know I'd rather not do house cleaning).
But anyway, today she came to me with an actual example of what she was basing her statements on. The kid was told to go help carry in groceries to keep my dad from doing it (my dad refuses to cave in to the limitations of his illness, and ends up hurting himself from overdoing). The kid took at least five minutes to get his shoes on-spending most of that time getting his laces tied right. For him, this was moving at light speed.
So later she pointed at that, and said, see, this is what I'm talking about. He spent that much time getting his shoes on, to avoid carrying the groceries. I told her that it wasn't the groceries. He was actually moving fast for him. It takes him on average ten minutes to get his shoes on when the little neighbor kids come to the door wanting him to go play. I know this isn't like the greatest story ever told, but she listened. I really believe she re-evaluated the scenario. That makes it a win in my book.