Sadly, this may have to get worse before it gets better. You’ve already done what I would suggest. As you already discovered, this can’t be handled long distance by phone and email. It needs people’s presence and persistence. But you did that with your visits. She also may need more time in a hospital to stabilize her medications and to establish the value of therapy. But she has already had one such stay.
It may require another crisis — and another hospitalization — to give you some leverage with her. In this sense, it might be more helpful for her husband to move ahead with his plans than to continue to try to reason with her. His gentle approach has inadvertently helped her remain convinced that he doesn’t mean it.
While she is in hospital, you could request a family meeting to learn more about her state of mind and to ask for advice about how best to support her. My hope is that such a meeting would persuade her to return to your country where she has on-going support. But she may not agree to do that.
I don’t know enough about Canadian law to advise you about whether there is anything you can do to compel her to accept treatment and go where she is loved and cared for. In your shoes, I would check with a lawyer to see.
Meanwhille, you are in the very difficult position of having to watch someone you love self-destruct. There’s nothing I can say to make that any easier. If there is a support group in your area for relatives of people who are mentally ill, I do urge you to attend. Such groups often provide both information and emotional support that are helpful.
I wish you well.