Bankruptcy (chapter 11) doesn’t mean the company goes out of business, or that the share price goes to zero. It means they renegotiate debts, after presenting a plan describing how they’ll be able to pay those renegotiated debts. If those debts can not be renegotiated, the company can not present a plan that offers paying them off, or the court rejects any part of the plan, then the company’s assets may be liquidated to pay any outstanding debts.

Being bought out would likely come before any of this, which again means the stock wouldn’t be worthless.