Charged with murder 30 years later

(Warning: IANAL) Causation is part of murder. If the victim himself induced sepsis, Person A could argue that the shooting did not cause death, ergo Person A did not commit a homicide.

Sounds like an argument for his lawyer to make to the jury at trial, not a reason for the prosecution to not charge him in the first place. (IANAL either)

I follow your logic to some degree & I am likely biased since I am dealing with an elderly parent with bedsores , which are very hard to prevent, even when following drs orders.

But on second thought, I would agree that the victim’s refusal to follow drs orders (if that is indeed what happened) should be considered as a mitigating factor, but a homicide charge is still appropriate imo.