CPS is charged with the protection of the children. The fact that you moved back in with your abuser is a possible indication that you were putting the children at risk by being in the same home with their father. Since he has been arrested and take from the home, the children would appear to be temporarily safe. But your actions may work against you. If I were you, I would sign up for some more classes through one of the women's shelters or a parenting class at CHOC or F.A.C.E.S.
BEcause the CPS case was closed, and there are no current allegations of Domestic Violence, it seems unlikely that CPS will investigate at this point.
However, your husband was arrested. What was he arrested for?
It seems that your husband has ongoing legal problems, which he has failed to take care of.
Had he been driving and arrested, this may have trigged a call to CPS, and you would have lost your children again.
In my opinion, you are putting your children at risk. You are willing to continue to accept his unacceptable behaivor, i.e. failure to take any classes which would have ensured the children could be returned to the two of you. This is abuse. You are still willing to tolerate the abusive behavior.
For your safety, and the health of your children, seek help.
Please note that this answer does not constitute legal advice, and should not be relied on, as each situation is fact specific, and it is not possible to evaluate a legal problem without a comprehensive consultation and review of all the facts and court pleadings filed in the case. This answer does not create an attorney-client relationship