Is temporary and lawful possession an affirmative or ordinary defense?

If your husband is planning to claim that he found the gun ( or took it away from someone) and was on the way to the precinct to turn it in, that would be transitory possession , which is an affirmative defense. Any evidence which would allow a juror to conclude that intent would require the judge to provide the jury instruction.

The process to get this information to the jury is to work with his public defender. Only he can help your husband with this issue unless you find the money to hire a good lawyer. You need to work with the public defender. They will be his voice.

The person who is best suited to answering your question is the public defender. Your husband needs to bring this to the PD's attention as soon as possible to get things moving.

The CJI on Temporary Innocent Possession states: "that the defendant is not required to prove that his possession of the weapon was innocent. The People must prove beyond a reasonable doubt both that defendant knowingly possessed the weapon and such possession was not lawful." I suggest that your husband's lawyer submit to the court a proposed jury charge that includes a copy of the CJI instruction on Temporary Innocent Possession. I would submit to the court a written proposed jury instruction at the commencement of the trial. I would even attempt to get the judge to discuss it in his preliminary instructions to the jury. If that is the defense strategy then your husband's lawyer should consider discussing it during jury selection, opening statements, cross examination of each witness and during the closing closing. The foregoing was stated without knowing the facts of the case.