Well, if the husband did not authorize the signing and objects to it, the wife could be prosecuted for fraud and could be found liable to the husband for any tax refund money that she was able to get because of filing the joint return. But as a practical matter, the timely submission of the joint returns may have been beneficial to both spouses. If the husband doesn't complain about it, no one else will either. If the husband was in jail he probably has more important issues to worry about.
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If the tax return was prepared by a professional, it was probably electronically filed. The preparer had form 8453 signed and should have it in the records. The best solution is to have another 8453 signed by the husband to confirm that it was his intention to file jointly. It is probably not a big deal.
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