What you are doing sounds great - just have him follow you around helping.
That is pretty much what I do, but in addition to my 4 year old daughter's posted "job list." In her case:
Feed cat every day
Make bed every morning (before school)
Water plants once a week
Help with laundry once a week
Pick up toys every day
Clean room every night (before bettime story)
I made a chart with simple words she can try to sound out like cat, bed, toys. I used stickers (cat, bed, broom, etc.) to help since she is pre-reading. I kept the list short - this is what she MUST do each week/day. I am really flexible, e.g., the bed is not ever made to my standards and the clothes are not folded the way I do. And at this age I am doing most of this alongside her. For the laundry, sometimes it is as simple as throwing the clothes in the machine, other times she helps me start to finish. Often, I can get it doen faster without her, but I want her to know she has a regular responsibility in this area and to make asymbolic effort.
I assume basic cleaning up after one's self, like putting her dishes in the sink, which she now does routinely And she has to help on big weekend projects, like cleaning out the garage.
She also likes to help me clean her bathroom. But I always open the windows or have her leave if I am using strong chemicals. I don't let her clean the toilet because I am afraid of chemicals splashing. She must wear a latex glove and she uses a clorox type wipe or a wet paper towel. Believe it or not , this is one of her favorite chores.