What does it mean when you have an immigration federal hold ?

The federal immigration hold means that there is a warrant for some reason. The hold notifies the facility to not release the person, but instead to transfer them to federal custody at the end of the jail term. An immigration hold may be placed after either a random check by ICE officers (who sometimes visit jails and interview inmates or after being notified by the law enforcement agency detaining the person. When DHS places a hold,  state law enforcement agencies are obligated to comply.

The domestic violence charge could carry some jail time, but it would appear that they have something that will send him to a federal facility.