This is new information, that your step-son is alone with you for 16 hours out of every day. If that is the case, then you and daddy would do well to come to a meeting of minds about whether or not your step-son needs discipline, and for what behaviors, and what that discipline should be. Agreement between the two of you is important, or your step-son will eventually learn to play you against each other. And who could blame him? It's what kids do as they try to establish their own independence.
If the discipline is effective and matched well to the behaviors, and if your step-son comes to see you as more than a mere babysitter, then some reasonable improvement is probably possible. But parenting is far more than lecturing or tattling on a child, and what you've described to us is that you only report misdeeds and add your own lectures on top of your husband's.
If I were in your shoes, I would start doing a lot of research on possible parenting techniques. All of us can make improvements in how to understand and communicate with children, what behaviors are reasonable and which aren't, how to apply discipline in ways that respect the child – even many babysitters work at that, and find simple but effective ways to control the children in their care.