It doesn't matter who the gun is registered to, if the gun was in your house where your husband was in a position to take custody and control of it. He is not allowed to have anything to do with ANY weapon. Period. When you live with someone who has no gun rights and keep a gun in the home, you are at risk for exactly what happened here if he knows you have a gun, can get to it, and something happens that brings the police to the house.
I am not saying that the police behaved correctly. I have no reason to know one way or the other. But can he be arrested and charged as a felon with a firearm based on what you've told me? Yes, absolutely.
Your husband will need a lawyer to fight his case, because they will likely not offer him anything he'll be excited about taking for this charge.
If you are expecting that your husband's case will be dismissed because you didn't like how the search and seizure of the weapons and the arrest went down, you are likely to be disappointed. That is not the way our system works. There is a procedure set down by the US Supreme Court
to explore and challenge constitutional issues. That means that if your husband wants to go to trial
on the case, his lawyer would file a motion asking for a pre trial suppression hearing to challenge the Constitutionality of the search, seizure and all that flowed from it to see if your husband's Constitutional rights were violated.
At such a hearing, the officer will take the stand, discus what brought him to the house, what he saw and did there, and how it led to your husband's arrest. Your husband's lawyer lawyer would get the opportunity to cross examine the officer and show how he violated your husband's rights through an unlawful search and seizure.
The standard that the court must use to judge such a hearing is what a reasonable officer would do under the same circumstances. If the judge finds the search unreasonable, any evidence that was unlawfully taken could not be used in your husband's case. Obviously, if the gun is suppressed as the fruit of an unlawful arrest, the state doesn't have much, if any ofa case left.
If you're going to go that route, however, make sure you do it through a lawyer. Unfortunately, judges give a great deal of deference to the judgment calls of police who are out in the field. So if the officer has any good and credible excuse for your search, the judge is likely to find the search lawful No pre-trial suppression hearing is ever a slam-dunk for either side, no matter how good the issues may be.
If you are unable to afford an attorney to represent your husband, he needs to plead not guilty at his arraignment and ask the court for a public defender.