I think I'm the one having the meltdowns lately.
When I was a child, I used to throw my coat on the floor in the closet because I didn't really care and I didn't want to take the few minutes to hang up my coat. I just wanted to get to what I wanted to do after getting home from school. I can remember mom telling me she wanted me to hang up my coat and I was being lazy. I didn't do it because I just didn't see why I needed to hang it up. I always said I had no time. When I look back, it was because I had no time to do it because I wanted to get to what I do. Because it wasn't important to me to hang up my coat, I didn't see why it was so important to my mother why I needed to do it. There were other things too I didn't care about so I never really listened because to me it wasn't important. Maybe if she used a punishment on me, it would have worked because I hated getting punished. That was my weakness there.
Then when I was nine years old, school had started foe the year again and my mom bought shelves for the closet and she put them together and made a section for us kids to hang up our coats. Mom told me if any of us threw our coats on the floor, there be a consequence and told us what the punishment be. One day I get home from school, I take off my coat and toss is on the floor and close the door. Right away I say "Oops" and I open the door and hang my coat up remembering what my mother had told me. All of a sudden it became important.
Then I got very obsessed with cleaning and I couldn't get my whole family to be clean and neat and couldn't get my brothers to pick up after themselves. Simply because they didn't find it important so they couldn't see why it was for me. My own dad is a slob too and he also doesn't see how it's important to be clean I assume.
So I'd say this is a kid thing. With AS kids, there needs to be logic for why you want it done. Even NT kids need logic also. Remember the famous "because I said so?" I hated that. I think that is something any kid would hate to hear. Then when I was 12 years old, I realized it was because my mother was too lazy to say why. So if people are going to be too lazy to explain the logic, then we are going to be too lazy to listen and learn. But as a child it always sucked when I had to suffer a consequence for not listening to the famous "Because I said so" and then I'd be pissed for getting punished because they couldn't they say so? I always did stuff just to see what would happen. If they would have told me, I wouldn't have done it.
Also picking up his mess may be too much information for him. He needs more information than "pick up your mess." In his head he is probably wondering "Where do I start?" "What are the steps" "Where do I need to put it?" "What do I need to pick up?" "Do they want me to pick up all of this or do they want me to pick up these cars or these action figures, which mess?" Aspies struggle in these verbal commands because they don't know how to break it into smaller pieces so you need to give them more information. Tell him what he needs to do to pick up the mess and where to put it. Then after a while he might understand what "Pick up your mess" means. It be done by rote.
It's like this, let's say someone hires you to clean their house for them. You look at it and it looks fine to you but you are going to wonder what do they want you do do. Do they want you to dust the furniture or polish. Do they want you to do the dishes or wash the floors, do they want you to do laundry and fold clothes, so they want you to organize their kitchen cupboards or clean their fridge? See you have no idea what cleaning they want you to do. You have all this information in your head you don't know what you are supposed to do. Maybe if they gave you a list of chores they want done, you'd have no problem with it.