After carefully reading your friends story, I definitely would report these threat's to her local law enforcement, and I would encourage her to definitely delete her Facebook account ASAP .Be praying for God's best and protection for your friend.
Hire a good lawyer and pay them to solve your problems. Or contact the county clerk in both counties and see if they can help you resolve this conflict and a simple misunderstanding.
I personally don't see anything wrong with the prosecutor commenting, on your social media account, as long as he doesn't ask you any personal questions, and does'nt discuss your personal business on social media. Just be careful and always protect your rights.