J.G.
My kids put away their clothes -I put bins in their closet and they just need to collect the cloths and put them in the right place. My 19 month old just carries them to her room, she shoves them in a draw, and I then put them where they actually go. It's cute :-) They are responsible for all their toys -toy room, office/craft area/ and playroom need to be tidy. We do sweeps a few times day, and before bedtime stories, the floor in their room needs to be clean.
And yes, at 4.5, he can get a lot of his own food. I have a snack shelf low to the ground-even my toddler can get crackers if she wants. I also let them buy things when we shop, they pick out their breakfast food, lunch food, and a dinner a week. My 4.5 year old is able to shower by himself as well, and he makes his own sandwiches, likes to wash dishes, etc. He is also responsible for collecting the garbage cans on garbage day from the bedrooms. And he does crumbs after meals with his kids broom and dust bin.
He orders his own meals when we are out, and if he wants something at a Store - like a sucker at trader Joe's, he need to ask for himself. I rarely speak for my kids. If they want something, they have to ask.
You need to figure out what his thing is. My son really likes to help me. My oldest gets confidence from helping her siblings. Figure out what he likes, and then go from there.