I would like to chime in with some of the other posters. i would bet that it is a combination of two things: 1) he's gotten away with not HAVING to do it right away, all the way, with a joyful heart. 2) He's probably totally overwhelmed. i often feel overwhelmed by the dishes myself! I realized for me, often having my kids do chores was almost a selfish thing; i didn't want to do that job either. Then attended a lecture by Susan Kemmerer at the CHAP convention. it was titled, "Servanthood 101: Teaching Kids to Serve." And it was basically a lecture about OUR spirits, OUR attitudes of service. All I could think was, UGH. SHe was so real. She has this lecture as a chapter in her AMAZING book called: Homeschool SuperMOM...NOT! I highly recommed it. But what I gleaned from it was this: Jesus never sent his disciples out without training or doing the job right BY THEIR SIDES. Application: can you share the job with him, help him so to speak, training him gently? Perhaps even breaking the job into steps, post it on a piece of card stock at the job site, so he can see the "pieces" of the job, would help? Maybe it could be a bit of special time together?
As for his attitude and obedience, I really really understand this one - finding appropriate consequences is so hard. I struggle with the same thing with my 9 yo son. Perhaps some of Raising Godly Tomatoes would help? Keeping him "staked" might allow you a closer insight into times when his attitude descends into the depths? Perhaps, if you're a believer, you could discuss Scripture with him, showing him how this points to his need for a savior? Some kids respond really well to a timer with with an incentive at the end? I've also seen other parents have great success with training first time obedience with a game. The parent sits with a bag of M & M's or skitttles or the like. THey give wacky and silly directions, increasing the complexity over time. Each time the direction is followed, they get one or two candies. It's a fun thing, but habits are being built. Then move to noticing when a child might be doing something else, and then calling them or giving a direction, and if they obey, they get an unexpected reward of candy or whatever.
Perhaps another thing is leveling with your son. Explaining how hard it is when everyone doesn't work as a team. Explain that not all job are easy or fun. But, we need to do them anyway. Explain that you don't wear his clothes, but you love him, so you wash them anyway, etc...and then tell him you understand that it's hard, so you want to give him incentive to get it done - so maybe he earns a pebble for doing each job done promptly, obediently. Perhaps another pebble could be earned for doing the job until it's done. When he earns "X" number of pebbles, he and you or the whole family get to do something special together, to celebrate teamwork?
Also, I would look for other chores that are managable for your 4yo dd. Dusting is manageable, folding washcloths and dishtowels, feeding a pet, scooping up toys to put back into a bin, etc. It will make it feel more like a team for your son. I know my kids feel so much better when they see a list and I am listed on it too, so they know we all have a part to play, you know?
Hope this helps,