My 16 year old inmate was arrested for threatening someone online by sending a video of a weapon. What is the possible jail time he will get?

JAil time is not as simple as the charge filed against a person. There are factors such as previous criminal history or even history with brushes with the law that create a profile of character (good or bad). If there are no priors and this act can be framed as a misguided juvenile prank, he might get lucky and get off with a pre-trial intervention where he would take some sort of anger management program or some classes similar to that. He might have to pay a fine. But, if there are a litany of incidents, the judge might think it's time to teach him a lesson. Please be mindful that this sort of act is not looked at like it might have been 20 years ago. Young people are committing violent acts against society far too often for this to be ignored. Not knowing your inmate's history, we think it could go either way depending on the judge.