Hello birdcrazy: I don't know as I have much of anything useful I can offer here. But I saw that no one had replied to your post, so I thought I would.

I'm not sure what you have in mind here as far as showing your uncle's posts to someone goes. Personally I don't know who you could show them to that would make a difference. Really, the only person who has any power in this situation is your uncle's wife. And her options are, unfortunately, limited. She could, perhaps, seek an order of protection. However, these often seem to be of little value when it comes right down to it. Unfortunately threats, in-&-of themselves, are not illegal in most cases.

Your concern for your uncle's wife is certainly to be commended. It may be that the best thing you can do is to offer her whatever amount of emotional support she would like & you are able to provide. From what you wrote, I would suspect she may appreciate a thoughtful gesture. My best wishes to you...