frank, forever the logical one here but.......I would see an attorney immediately - like this week, today - to find out about the implications of buying a house while your situation is so unstable. You're right - if she continues on this path, she will reap the benefits of this, you won't. I would NOT be acquiring such a major asset right now....it is extremely unwise.
There are other houses out there to buy. They aren't going away. And you can protect yourself if you can find a loophole to get out of this sale. Please talk to your lawyer.