Can I be sued for the credit card account?

Your statement of facts not clear. If you were authorized to use the card there is no fraud. But if you used it you are liable to pay the bill.

Yes. If you are sued, don't ignore it. Send a letter to the court denying that you owe all that is claimed and demand an accounting of all charges. That will delay things a bit. You are responsible unless you can show your father gave you permission to charge. Like a letter from him or proof that he made payments on the account as you were charging, implying agreement with your ongoing use. If the charges are after his death, of course you are responsible. If you were less than 18 years old for any of the charges, you can claim your father was supporting you. The honorable course is to pay the charges you made. Your papa's reputation is at stake, at least symbolically. The spirit of your father may be watching. Some believe that death is not an ending but a beginning. See you on the other side.

Your exact question is whether or not you can be sued. Of course, you can be sued. Lawsuits are filed every day, but defendants win many of those lawsuits. So the real question is whether or not you are liable (legally responsible). If you used the credit card with your dad's consent and he was competent to give consent, then you did not defraud him. Note: If you kept charging on the credit card after your father became elderly and incompetent, some state's may consider that a form of undue influence or elder abuse. Whether or not you are liable to the credit card company for the account balance depends on what you signed, and may be impacted by the common law of your state. If you received the benefit of the credit card (i.e., ate the meals charged on the credit card, have the television bought with the credit card, etc.), then you might be liable to the credit card company for quantum meruit (an implied contract theory meaning "as much as deserved").

Can she? Of course. Can she win? It will be up to you to prove the arrangement you and your father had. If you can show you were charging and making the payments and were an authorized user, you should be able to avoid the fraud charge. Whether you can be held responsible to pay is a different question. If your father had a probate, the credit card account would have gone through that process.

If the account is/was in your father's name & you were merely a user, then you are not legally responsible for the debt absent some executory agreement related to your father's will, etc.

Whether you can be made liable for this credit card account depends largely on how it was being used and how it was set up. The credit card holder can allow others to use their card without being liable on the account. However, if you were actually on the account then you could be liable to the credit card company for the balance of payments. As far as the surviving spouse, she is now being asked to make the payments undoubtedly it if you had been using the credit card as your own personal credit card, she may have a case against you.

It isn't fraud because your dad put you on the account as a user. He gave you his permission to use the card, so you only did what he permitted you to do. Fraud is where you deceive someone by making a false representation. Of course, someone could try to say that you tricked him into it or forged his name, but that gets into some detailed evidenciary issues.

I hope you didn't charge anything after he died. Otherwise, I think you're okay.

I'm not sure if she can or can't because you mentioned fraud. If you committed fraud then she may be able to, but from what you describe it sounds doubtful.

I don't think your dad would have anything relevant to say if you signed an agreement with the card issuer to be liable for the amount that now remains unpaid. If the credit card issuer goes after you tell them to produce all evidence that you are liable. You could offer to settle for a fraction of the amount. "Bill collectors" usually buy the accounts for maybe five cents on the dollar, so they can make money even with a small settlement. Seems like you did no "fraud." If there is a law school anywhere near you it may have a clinic with law students who can help you for free. You can call NOLO Press in Berkeley to see if they have a book that would help you. Do creative google searches.

I would have to read the contract to advise you on your liability to the company. However, if the widow is suing you for fraud, my guess is that you are not liable to the company. Rather, your Dad signed up for the card solely in his name and you were just an authorized user, making his estate solely liable for the debt. I assume the widow is suing you for fraud because this debt is cutting into what she will get. I assume that she is alleging that you fraudulently opened the card in your father's name without his permission or knowledge. She would have the burden of proving this, and such a case would involve an obscure law known as the dead man's statute that limits evidence of business transactions involving a person who is dead and cannot testify about the transaction. The rule prohibiting hearsay evidence would also limit the widow's ability to testify about any conversations she allegedly had with your father about the card. It is possible that you and your father are liable for the debt on the card, and she is suing you for fraud because even if you are jointly liable, the company can go against the estate for the whole amount unless you fraudulently opened the card, in which case, the estate would be off the hook.

Anyone can sue you. If you used the card you owe the credit card company. Your stepmother has a much weaker case and I would need more facts before answering you.