Absolutely, and it is one of the more straightforward paths to the hole that exists in any correctional facility.
Guards are there to maintain order, and an inmate verbally assaulting a staff member is a direct challenge to that order. It does not matter whether the words were said in anger, frustration, or as a heat of the moment reaction. Disrespecting or threatening a corrections officer is a serious disciplinary infraction at every facility, and the standard response is removal from general population and placement in segregation. Some facilities classify it as a minor infraction and handle it with a shorter sentence in the hole. Others treat verbal abuse of staff more severely, particularly if the language was threatening rather than just profane.
Your son is physically safer in the hole than he would be if this had escalated into something physical. The isolation that makes the hole psychologically brutal is also what keeps him away from any conflict with other inmates while he serves out the disciplinary time. Nobody is going to get to him in there.
The harder part is the emotional weight of it. Solitary confinement is genuinely difficult in ways that are hard to describe to someone who has not experienced it. The silence, the sameness, and the complete absence of stimulation accumulate quickly. Every minute can feel like an hour.
When he gets out of the hole, encourage him to be smarter about how he handles frustration with staff going forward. There is almost no situation inside where mouthing off to a guard produces a better outcome than staying quiet and filing a grievance afterward. The hole is hard time that serves nobody well.