Besides legal help, you can help ease your mother's anxiety about the upcoming court date by having her consider granting you a power of attorney that would allow you to represent her interest in this matter in court. With the power of attorney you will have the authority to appear in court on your mother's behalf, and she will not have to appear. You can create the power of attorney document yourself at USLegalForms.com, but I would encourage you to have an attorney review the form to assure that it meets the requirements in your state before the court appearance.
Whether you decide to use an attorney or appear on your mother's behalf, or if she appears and you go with her, I would suggest that you research the statute of limitations for using the courts to collect a debt in your state. This debt is 6 years old, so it may be past the statute of limitations. If it is, then the statute of limitations is all the defense she'll need, regardless of whose debt it really is. Just tell the court the debt is uncollectible due to the statute of limitations, and you will be done.
Should the debt be within the statute of limitations to collect, then let the court know the debt is not your mother's and that she received no proof that the debt was hers. Request that the case be dismissed. It is likely that the collector does not have the proof required. My guess is that the collector is hoping your mother will not appear in court and as a result they would pick up an uncontested default judgment.
Depending on how much time you have before the court hearing, you may be able to shelter your mom by notifying the collector that you have your mother's power of attorney in regards to the collection of the debt. Request that the collector provide proof that the debt is your mother's, ideally something with her signature on it. At the very least, it would be good to get copies of doctor and/or hospital bills including your mother's name and other identifying information. If they can't, then send them a letter (certified mail with a return receipt) restating that the debt is not hers and demand that they not communicate with you or your mother about the debt again. The Fair Debt Collection Practices Act prevents the collector from making further contact after receiving this request except to let you know of any planned activity. This may not stop further court action, but it will end collection calls and letters.
Should the collector send you proof that the debt is your mother's, the debt is still uncollectible because you mother has no real property or assets and her sole source of income is Social Security. Social Security benefits are exempt from garnishment except for government debts and child/spousal support. The bank will automatically protect her Social Security funds (up to the amount of the previous two months' worth of deposits) from garnishment as long as they are direct deposited into her account. However, if there are other funds not from Social Security in there, close the account and set up a new account that will only receive her retirement benefits.
However you decide to proceed, handling all further communications from the collector for your mother will be a blessing for her in this stressful situation.
Ask the adviserTo ask a question of the Debt Adviser, go to the "Ask the Experts" page and select "Debt" as the topic. Read more Debt Adviser columns and more stories about debt management.