There is something that I am reluctant to bring up but leaving aside the alleged facts in this particular situation, a defense exists of lesser harms which is a form of necessity defense. That is a person should not have to suffer a greater harm if a lesser harm can prevent it. This is pretty much a last ditch defense used most often by people that admit doing a particular crime in order to prevent a greater harm befalling them. Most states restrict the ability to mount such a defense because generally speaking one must assert such a defense with clean hands aka not being involved in a crime at the time such as a robber cannot claim self defense for shooting the homeowner because the homeowner had a gun. Gets more complicated with past felonies or misdemeanor domestic violence/protective orders , etc. because the prohibited person may not be engaged in one of the forcible felonies at the time they assert a necessity arises such as self defense.
For example, assume that a prohibited person exists, that does not override their right to self defense. Virginia is apparently such a state,
https://caselaw.findlaw.com/va-court-of-appeals/1137898.html
William Michael HUMPHREY v. COMMONWEALTH of Virginia, Va. Court of Appeals, Record No. 1982-00-2. Decided: October 23, 2001
"William Michael Humphrey (appellant) appeals from his jury trial conviction for possessing a firearm after having been convicted of a felony in violation of Code § 18.2-308.2. On appeal, he contends the trial court erroneously concluded that he could not assert necessity or self-defense as a defense to the charge and, therefore, erroneously rejected a proffered jury instruction on self-defense. We hold that the common law defense of necessity remains available, upon an appropriate factual predicate, as a defense to a charge of possessing a firearm after having been convicted of a felony under Code § 18.2-308.2. Here, the evidence, viewed in the light most favorable to appellant, entitled him to such an instruction. Therefore, we reverse his conviction and remand for additional proceedings consistent with this opinion."
The gist of it is that a group of people meeting at a trailer get into it and a threat is issued by a departing party. Shortly thereafter, someone in a pickup truck closely resembling the one driven by the threatening parties, starts shooting at the trailer. One person flees to a shed, and gets a shotgun there that he knows his father keeps there. He fires into the air twice and terminates the assault as the people shooting at the trailer leave. He is a former felon and prohibited person and is charged by VA as such. The judge at the trial did not allow a defense of necessity that the felon needed to possess and fire the shotgun to repel the assault (and violated the law) in order to prevent a greater harm (death or serious injury to himself and others). VA Court of Appeals agreed and sent it back for retrial with the order that the appellant can put forward this defense to the jury.
The Court of Appeals continues,
“The law of self-defense is the law of necessity.” McGhee v. Commonwealth, 219 Va. 560, 562, 248 S.E.2d 808, 810 (1978).
The [common law] defense of necessity traditionally addresses the dilemma created when physical forces beyond the actor's control render “illegal conduct the lesser of two evils.” ․ The essential elements of this defense include: (1) a reasonable belief that the action was necessary to avoid an imminent threatened harm; (2) a lack of other adequate means to avoid the threatened harm; and (3) a direct causal relationship that may be reasonably anticipated between the action taken and the avoidance of the harm."
As Kleenbore said above, VA still has a lot of common law in its system.
Other states also have similar statutory or common law provisions but not all of them. So YMMV.
For example, assume that a prohibited person exists, that does not override their right to self defense. Virginia is apparently such a state,
https://caselaw.findlaw.com/va-court-of-appeals/1137898.html
William Michael HUMPHREY v. COMMONWEALTH of Virginia, Va. Court of Appeals, Record No. 1982-00-2. Decided: October 23, 2001
"William Michael Humphrey (appellant) appeals from his jury trial conviction for possessing a firearm after having been convicted of a felony in violation of Code § 18.2-308.2. On appeal, he contends the trial court erroneously concluded that he could not assert necessity or self-defense as a defense to the charge and, therefore, erroneously rejected a proffered jury instruction on self-defense. We hold that the common law defense of necessity remains available, upon an appropriate factual predicate, as a defense to a charge of possessing a firearm after having been convicted of a felony under Code § 18.2-308.2. Here, the evidence, viewed in the light most favorable to appellant, entitled him to such an instruction. Therefore, we reverse his conviction and remand for additional proceedings consistent with this opinion."
The gist of it is that a group of people meeting at a trailer get into it and a threat is issued by a departing party. Shortly thereafter, someone in a pickup truck closely resembling the one driven by the threatening parties, starts shooting at the trailer. One person flees to a shed, and gets a shotgun there that he knows his father keeps there. He fires into the air twice and terminates the assault as the people shooting at the trailer leave. He is a former felon and prohibited person and is charged by VA as such. The judge at the trial did not allow a defense of necessity that the felon needed to possess and fire the shotgun to repel the assault (and violated the law) in order to prevent a greater harm (death or serious injury to himself and others). VA Court of Appeals agreed and sent it back for retrial with the order that the appellant can put forward this defense to the jury.
The Court of Appeals continues,
“The law of self-defense is the law of necessity.” McGhee v. Commonwealth, 219 Va. 560, 562, 248 S.E.2d 808, 810 (1978).
The [common law] defense of necessity traditionally addresses the dilemma created when physical forces beyond the actor's control render “illegal conduct the lesser of two evils.” ․ The essential elements of this defense include: (1) a reasonable belief that the action was necessary to avoid an imminent threatened harm; (2) a lack of other adequate means to avoid the threatened harm; and (3) a direct causal relationship that may be reasonably anticipated between the action taken and the avoidance of the harm."
As Kleenbore said above, VA still has a lot of common law in its system.
Other states also have similar statutory or common law provisions but not all of them. So YMMV.