Here is the law.
I have boldfaced what I believe will be the contested issues that will be submitted in the jury charge.
I've struck thru the things that I believe will not be relevant
NOTE: first of all, use of force or deadly force for self defense is a "defense" under the TPC Ch 9, therefore this law applies:
Sec. 2.03. DEFENSE.
(a) A defense to prosecution for an offense in this code is so labeled by the phrase: "It is a defense to prosecution . . . ."
(b) The prosecuting attorney is not required to negate the existence of a defense in the accusation charging commission of the offense.
(c) The issue of the existence of a defense is not submitted to the jury unless evidence is admitted supporting the defense.
(d) If the issue of the existence of a defense is submitted to the jury, the court shall charge that a reasonable doubt on the issue requires that the defendant be acquitted.
NOTE: So the state has to disprove, beyond a reasonable doubt, that the defense does not apply. This is a huge hurdle for the state, who has to prove their case beyond a reasonable doubt, and then disprove the defense beyond a reasonable doubt.
NOTE: if there was a passenger in the car, he will also likely get a jury charge on deadly force to protect a third party
Sec. 9.31. SELF-DEFENSE.
(a) Except as provided in Subsection (b), a person is justified in using force against another when and to the degree the actor reasonably believes the force is immediately necessary to protect the actor against the other's use or attempted use of unlawful force.
NOTE: the above clause of section (a) is the general rule, and within it is a presumption that is submitted in the jury charge if there is some evidence of it. If the state fails to eliminate reasonable doubt as to one of the elements (1-3) below the jury must follow the presumption, and presume the actor’s belief that the force used was immediately necessary was reasonable. This is huge in a self defense case. If the jury has reasonable doubt whether these circumstances existed, it is devastating for the state’s case.
(section (a), cont’d) The actor's belief that the force was immediately necessary as described by this subsection is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the force was used:
(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment; or
(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or
(C) was committing or attempting to commit aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery;
(2) did not provoke the person against whom the force was used; and
(3) was not otherwise engaged in criminal activity, other than a Class C misdemeanor that is a violation of a law or ordinance regulating traffic at the time the force was used.
NOTE: the use of force may not be justified under certain circumstances in this case and there will be a jury charge on this issue. If the state can prove, beyond a reasonable doubt, that one of these circumstances existed, then it is a huge win for the state.
(b) The use of force against another is not justified:
(1) in response to verbal provocation alone;
(2) to resist an arrest or search that the actor knows is being made by a peace officer, or by a person acting in a peace officer's presence and at his direction, even though the arrest or search is unlawful, unless the resistance is justified under Subsection (c);
(3) if the actor consented to the exact force used or attempted by the other;
(4) if the actor provoked the other's use or attempted use of unlawful force, unless:
(A) the actor abandons the encounter, or clearly communicates to the other his intent to do so reasonably believing he cannot safely abandon the encounter; and
(B) the other nevertheless continues or attempts to use unlawful force against the actor; or
(5) if the actor sought an explanation from or discussion with the other person concerning the actor's differences with the other person while the actor was:
(A) carrying a weapon in violation of Section 46.02; or
(B) possessing or transporting a weapon in violation of Section 46.05.
(d) The use of deadly force is not justified under this subchapter except as provided in Sections 9.32, 9.33, and 9.34.
NOTE: The above is the rule for use of force for self defense, not the use of deadly force for self defense which is in 9.32, so we have to look at 9.32 as well due to 9.31(d) and 9.32(a)(1).
Sec. 9.32. DEADLY FORCE IN DEFENSE OF PERSON.
NOTE: section (a) is the general rule on deadly force.
(a) A person is justified in using deadly force against another:
(1) if the actor would be justified in using force against the other under Section 9.31; and
(2) when and to the degree the actor reasonably believes the deadly force is immediately necessary:
(A) to protect the actor against the other's use or attempted use of unlawful deadly force; or
(B) to prevent the other's imminent commission of aggravated kidnapping, murder, sexual assault, aggravated sexual assault, robbery, or aggravated robbery.
NOTE: the same “presumed reasonable if…” elements that we looked at in 9.31 above also apply in 9.32 below.
(b) The actor's belief under Subsection (a)(2) that the deadly force was immediately necessary as described by that subdivision is presumed to be reasonable if the actor:
(1) knew or had reason to believe that the person against whom the deadly force was used:
(A) unlawfully and with force entered, or was attempting to enter unlawfully and with force, the actor's occupied habitation, vehicle, or place of business or employment;
(B) unlawfully and with force removed, or was attempting to remove unlawfully and with force, the actor from the actor's habitation, vehicle, or place of business or employment; or
(C) was committing or attempting to commit an offense described by Subsection (a)(2)(B);
(2) did not provoke the person against whom the force was used; and
(3) was not otherwise engaged in criminal activity, other than a Class C misdemeanor that is a violation of a law or ordinance regulating traffic at the time the force was used.
NOTE: similarly, section (c) and (d) in 9.32 is the same as 9.31(e) and (f) and creates an instruction for the jury, where applicable
(c) A person who has a right to be present at the location where the deadly force is used, who has not provoked the person against whom the deadly force is used, and who is not engaged in criminal activity at the time the deadly force is used is not required to retreat before using deadly force as described by this section.
(d) For purposes of Subsection (a)(2), in determining whether an actor described by Subsection (c) reasonably believed that the use of deadly force was necessary, a finder of fact may not consider whether the actor failed to retreat.
NOTE: if the state fails to disprove this beyond a reasonable doubt, the jury gets an instruction that they shall not consider whether the actor failed to retreat in determining whether the actor reasonably believed that deadly force was immediately necessary under the circumstances.