If she gets in over her head in real estate, is there any reason she can't drain the assets of the company and shut it down overnight to pay debts racked up from construction?
Corporations are legal entities and as such have its own assets, that are managed independently from the owner's and employee's.
As such, the owner cannot freely dispose of the corporation's assets, if that means that the corporation will no longer be able to honour its obligations. If you were owned $100,000 for your work, but the proceeds of selling your work were pocketed directly by the owner, then if the corporation claimed bankruptcy ("no money to pay you because the customers do not pay us but the owner") you could go after the owner.
At any time the owner may decide to liquidate the corporation. As long as you are paid what you are due (both in accrued salaries and severance package), you have no recourse. But that is not different from the corporation deciding to fire you for whatever the reason.
Alternatively, if in need of cash the owner may decide to sell the corporation to someone else. But that would not affect your legal relationship with the corporation (of course, new ownership might mean new management and other changes).
If the corporation does nothing illegal, the owner and manager are protected in case of bankruptcy. If they owe you $100,000 and the corporation only has $10,000, it can claim bankruptcy and you will get at most (dependent of other debts) those $10,000; you cannot then try to recover the rest of the money from the manager.
In short, the obligations of the corporation towards you are those derived from the work contract (and related laws). If the corporation upholds those obligations, you are not entitled to anything more (if you are fired legally and paid what you are due, it does not matter if it is because the corporation was liquidated or any other reason).