seasider
It was a very expensive mistake I made (basically trusting him - probably your daughter also trusted her husband to play fair). There's nothing you can do about ownership of the company but you can protect her right to income from it (that, he cannot keep all to himself as it forms part of the assets). You do need to move quickly - don't give him time to start moving assets about that ends up with your daughter needing a forensic accountant (which is what I would have needed) to track them down.
by making her a shareholder
If the husband is the sole, or majority, shareholder, it is unlikely that he would willingly put shares up for sale (and he is under no legal obligation to do so).