Child abuse hearing?

When boyfriend is arrested, as soon as mom calls the po-po, boyfriend goes away in handcuffs. Mom is advised to get her butt to court and get herself a restraining order immediately. This is served on boyfriend immediately if he's still in custody, soon as he's next found if he's already been released to a third party or on his own recognizance. But even if the RO isn't served, a condition of release is almost certainly set by the judge he's to have no contact w/ vic and mom.

Boyfriend's criminal trial comes at least weeks and weeks, more likely months and months later. If boy blurts out on stand (likely a jury trial, not just in front of judge but we're not clear if the boyfriend's assault on the kid amounted to a felony) that mom assault him, judge may order kid to foster care then or ask about other arrangments-may also hose the boyfriend's trial. Mistrial could be declared, retrial will depend on the case. Close cases aren't often retried by the prosecution, but a strong DV case will likely be retried. Anyhoo, mom now gets investigated for assault, too.
Note, the judge doesn't "know" the kid is telling the truth just because someone else corroborates the story. Also, folks don't generally just stand up out of the blue and offer testimony. The defense gets to have a list of who the prosecution will call. The defense can surprise the prosecution with witnesses however, so maybe the defense was going to call this person and had poor control/info on what the person would say.

How do you want it to work? If your story needs x to happen before y with a result of z, might be able to get you there.
Alzo, this info is for US, which is remarkably hardcore in the mandatory physkical arrest for even misdemeanor DV.

This is all going to be problematic if the kid is 18. He isn't entitled to foster care, AFAIK.

The mother & step-dad might get prosecuted, but the kid may be stranded with no help. It's a tough age. Most kids that age are still kids, but *legally* they are adults.

Depending on the state, 18 may be prosecuted the same as an adult assault. In Texas, that would be treated as an adult assault and it would depend on the injury to decide if it's a felony or misdemeanor. This would also have an impact on the amount of time it takes to trial.