I'll be frank: making kids make their beds every day IS stupid. There is simply no reason for it unless someone is coming over. It benefits no one, unlike countless other chores they could be doing. There's no logical defense at all for making your bed. It's just busy work.

Just tell him it prevents creepy crawlies from getting on him while he sleeps. I personally make my bed everyday because you just never know what could have crawled between them while your sheets are all crumpled up. It's saved me quite a few times and lets me sleep better at night.

What happened to just punishing a kid when he ignores his parents' directions?

So stop washing his dishes, because he'll eat of his plate again and use his fork again. This should make him more disgusted, because you see the filth and you don't have to use it, too, so sooner or later he'll want clean dishes like you have. Does he shower regularly? I know from my brother, that boys don't really care about that either, you need people from outside to tell them they're nasty, they won't believe you.

"Why feed you when you're going to die anyways?" Another approach.

Your lazy response caused him to think smarter and not harder.

Good job making the house unsanitary, mom!

Sometimes "because I said so" is the best answer.

I read that it's actually healthier to have an unmade bed than constantly making it

Jump on the bandwagon with him and watch as he realizes that he has to flush the toilet or he'll never be able to use it again.