poor little fellow. nothing in his world is safe. mom disappeared, then came back with another human for him to adjust too, and he has no assurances that mom won't just disappear again, and what will now happen to him AND a baby?
i suggest that instead of trying to think of ways to *control* him you look for ways to reassure him. i'm sad for him that spanking is even on the table. i'm glad the threat of CPS (who called them and why??????) means he won't get hit for acting out in his terrible fear and insecurity, but that's cold comfort.
since he was doing better with his dad, maybe that's the solution. does his father have a secure situation, where your son would feel safe? i'm a little surprised that you were sent home with a new baby and just had your other child plopped back on you. do you have ongoing support, and does your son have a therapist?
sounds to me as if he's thrashing around desperately, unconsolably terrified. being mouthy and not turning in his homework are symptoms of a deep underlying lack of confidence in his world, they're not problems in and of themselves.
put him first. either send him to live with his dad, if that's what's best for him, or dig in and put in the time to make him feel safe and confident that his world isn't going to be constantly upended. and that won't happen just because you say so. you have to demonstrate it over the long term.
i'm glad that you went into a program. i hope you're committed to staying out of whatever got you in there. i hope your children come first and foremost in your life now. but when you wreck that, you don't get it back easily. if you really want to be a good mother to your children, keep your eye on the long term, and don't get distracted by short-term issues that YOU have caused, and don't go for awful short-term fixes like spanking.
make your children safe.
khairete
S.