Just want to add that letting DIL know you're serving her with papers is only likely to anger her a little sooner. I doubt you can persuade her that you're "trying to do the right thing" if you're telling her you're taking her to court.
Also, as someone else said, that might just alert her and give her a head start in fighting you, either by letting you have some visits to negate your case or whatever else. If you wanted to get together with her to find out what you could change, if anything, to regain access to your GC, fine. But that's something that should have been done, if you wanted, before you opened a court case. But to give her a headsup that you're taking her to court? No. I don't think so.
When a political leader lies on their CV - can you trust them?

