(5) Returns made by agents. The return of income may be made by an agent if, by reason of disease or injury, the person liable for the making of the return is unable to make it. The return may also be made by an agent if the taxpayer is unable to make the return by reason of continuous absence from the United States (including Puerto Rico as if a part of the United States) for a period of at least 60 days prior to the date prescribed by law for making the return. In addition, a return may be made by an agent if the taxpayer requests permission, in writing, of the district director for the internal revenue district in which is located the legal residence or principal place of business of the person liable for the making of the return, and such district director determines that good cause exists for permitting the return to be so made. However, assistance in the preparation of the return may be rendered under any circumstances. Whenever a return is made by an agent it must be accompanied by a power of attorney (or copy thereof) authorizing him to represent his principal in making, executing, or filing the return. A form 2848, when properly completed, is sufficient. In addition, where one spouse is physically unable by reason of disease or injury to sign a joint return, the other spouse may, with the oral consent of the one who is incapacitated, sign the incapacitated spouse's name in the proper place on the return followed by the words “By __________ Husband (or Wife),” and by the signature of the signing spouse in his own right, provided that a dated statement signed by the spouse who is signing the return is attached to and made a part of the return stating:

(i) The name of the return being filed,

(ii) The taxable year,

(iii) The reason for the inability of the spouse who is incapacitated to sign the return, and

(iv) That the spouse who is incapacitated consented to the signing of the return.