1. (a) A New York State personal income tax return or other document (where a signature is required) of a husband and wife (if not made by an agent) must be signed by both spouses. If signed by one spouse, individually and as agent for the other, authorization for such action must accompany the New York State personal income tax return or other document. The spouse acting as agent for the other must, with such other spouse, assume responsibility for making the New York State personal income tax return and incur liability for the penalties provided for erroneous, false, or fraudulent New York State personal income tax returns. However, if the signature or authorization of either the husband or the wife cannot be obtained because of absence or illness, and no power of attorney or written authorization is available for the same reason, a New York State personal income tax return or other document signed by one spouse and offered to the Tax Commission for filing as a joint New York State personal income tax return or other document may be accepted as such if all the evidence indicates that the taxpayers intended to file it as a joint New York State personal income tax return or other document.
2. (b) In the case of death of one or both spouses during the year for which a joint New York State personal income tax return is made under the circumstances referred to in section 151.11(b) of this Article, the signatures and evidence of authorization required under the Internal Revenue Code and applicable regulations for such purpose will apply for New York State personal income tax purposes.

Tax Law, § 653(a)