Hmm. Tough call. It's it public info that t made public? Or matter of public record? And how did you find out the person is coming back?
I guess I would err on the side of caution and mention to t you found this info. If you know the person returning outside of t, you could simply mention you know he is on his way back with intent to contact family... having seen what restraining orders can do (or not do), I would probably give t the heads up and deal with the questioning around how you have that info after the fact. If he's dangerous enough to warrant a restraining order, he's dangerous enough to act on any impulses or plans to hurt the people that have the restraining order against him.