I really don't understand why you didn't set very specific boundaries when you first started this set up OP?? Or is it that you try to set boundaries, but he just walks all over them, and you can't seem to stop him?
It really doesn't sound like he's happy being a SAHD, so I would sit him down and talk to him. Tell him that you're unhappy that he's not fulfilling his role, and that expecting you to step in to do ANYTHING for him, or your child, is simply not on between the time you start your working day, and the time it finishes. If there's a wash to be put on, HE does it. If it's ready to go out on the line, HE does it. If there's shopping to be done, HE does it, and takes the LO with him. Lay out all of the scenarios where he's gone wrong, and tell him this has to stop, or he will need to get a job, as you can't put your own job at risk, filling in for him, while he 'just' nips down the shop, 'just goes out to the washing line', etc. He needs to take the LO with him, or make sure that he/she is safe, while he does things, like a SAHM would do.
I would also make a list of the household tasks that he needs to do on a regular basis, and then a separate list of things that he should do, once a month or whatever. Then make sure he does them - get him to tick it off, each time so that he can see what he's done and not done if it helps. It seems that a lot of men simply don't realise how much work goes into running a home, and so the jobs we do without even thinking, don't come naturally to them, hence the need for lists until he gets into the swing of doing all the things a SAHM would do.