She acknowledged he was in poor health to begin with. She described chronic conditions, as well as acute symptoms occurring immediately prior to the altercation. They stopped at the store because his arms and legs were cramping up “due to an infection,” and he thought potassium would help.
Infection can cause acute renal failure. One of the early symptoms of acute renal failure is general cramping due to electrolyte imbalances. I think that it rather likely the kidneys were “injured” prior to the altercation and not during it.