If she bought the second house and the property, those should be hers, yes.
So, it sounds like the major issue is that together they invested some shared money and the investment went poorly. So, the problem isn't that she's taking him to the cleaners, or that she found a loophole, or that he remarried, but rather that he invested his money and the investment went poorly. Is that right? A terribly crappy event, especially for someone his age. Argh.
But yes, he can be totally financially well if he's willing to sell and move to what he actually needs. There will be emotional losses in that, for sure. But there will also be major gains: financial ease, simple maintenance (freedom), etc. And these can go a long way in terms of happiness! It is likely he would need to release the house eventually anyway, if ever long term care is needed, for example.
(Sometimes I'm especially grateful that I haven't had a house to lose. I did own once, and loved it, and planned to retire in it. But I sold after only a few years and am grateful to live in places I am unattached to, so that I can keep moving to cheaper ones!)