Can a family member sign a 2255 petition on behalf of a defendant?

Petitioner Cardin's 28 U.S.C. section 2255 deadline was fast coming due.  But at the wrong time, disaster struck.  Cardin was hospitalized.  So he did the only thing he could - he had his sister (who had power of attorney for him) sign a draft of the 2255 he was preparing, and had her file it for him.  She did not disguise her signature as his; rather, she wrote "Walter Cardin by Natalie J. Cardin".  A couple of months after this filing, the district court sua sponte questioned whether the 2255 should be dismissed, as it was not signed by the petitioner.  Cardin filed a response, in which he attached: (1) a latter from his case manager at the BOP showing that he was in the hospital during the deadline time-frame, and (2) the power of attorney he had previously executed for his sister.  He also offered to amend the document with his actual signature.  The district court rejected this, and dismissed the 2255.

On appeal, the Court explored the "next friend doctrine."  "[A] ‘next friend’ must provide an
adequate explanation—such as inaccessibility, mental incompetence, or other disability—why
the real party in interest cannot appear on his own behalf to prosecute the action.' Id. 'Second,
the ‘next friend’ must be truly dedicated to the best interests of the person on whose behalf he
seeks to litigate.'"  Pursuant to this doctrine, Cardin's actions (and those of his sister) were entirely appropriate.  Further, the Court noted that "The courts should not impose on litigants (much less pro se ones) standards of diligence that nobody meets in practice."  The Court therefore remanded for consideration of the petition on its merits.

LINK TO OPINION HERE