Your first step is probably to explain to the man you live with why you disagree with his parenting, and to make sure you have a reasonable way to approach the problem ready as well. Tell him how you think it should be handled, and why you think your approach would work better.
I don't get the sense you have kids of your own, right? I might be wrong here, but if I'm not, you go into that discussion at an even bigger disadvantage. Since not only are they not your kids, but from what experience can you tap in order to tell him how parenting ought to be done?
But you'd better have that discussion, because if his type of parenting makes you furious, your relationship is going to suffer under it.