Will I make my current situation with my son worse?

Where is the boy's bio-dad? Good age for him to find and help the boy

I don't understand why your hands are tied because of your husband's past. You are entitled to avail yourself of the public sevices in your home, including the police. Are you concerned that they won't give the matter priority, or are you more concerned about what your husband's reaction will be if he learns you have called the police? You should call the police to see if they can help, but if you're worried about your husband, maybe you should call from someplace besides your home. Is your husband's felony in the past, or does he have active warrants now? If he is not wanted now, he shouldn't have much trouble with you calling them about your son. I hope.

Your son's father should be involved. He might be the answer to whatever is troubling your son.l Nonetheless I do not see any problem with your husband/step-father's unrelated felony if indeed a problem is not occurring between him and your son.