Interesting. There must have been cases of this somewhere already in the JW world. I wonder how the local elders handled it, and if it's the sort of thing they have to contact the branch for legal advice about?
Since the 1970s at least, they've used the scripture at 1 Corinthians 7:13 where it says if the husband is "agreeable to dwelling with her" she should stay together with him, but reasoned that clearly domestic violence shows he would not be "agreeable", so she can choose to separate from him (although they remain scripturally married) - but I can't find any mention in their indexes of protective orders and how they would be viewed. If both the partners are baptised witnesses it could be they would disapprove on the grounds of "not taking a brother to court" or something like that, on the other hand they might say it's a personal matter based on the above scripture and the wife taking reasonable steps for her safety (and their children, if any).
Good question!
Why don't they address important real life questions like this one in "Questions from Readers" rather than obscure points about the Israelite priesthood or whatever, that hardly anyone now cares about? (Ok, we know the answer to that - subjects like this are too controversial for them to want to open those cans of worms, and would hint at the truth that all is not well in many JW marriages! But that's realistic and would really show practical benefit from the scriptures.)