IOWA CITY, Iowa — Emergency responders and a hospital that treated a Cedar Rapids man for a gunshot wound after he allegedly killed his parents and sister must share his medical records with prosecutors, a judge ruled Tuesday.Alexander Jackson, 20, is charged with first-degree murder in the June 15 shooting deaths of his parents, Jan and Melissa Jackson, and 19-year-old sister Sabrina at the family’s Cedar Rapids home.Prosecutors say that after killing his family members, Alexander Jackson called 911 to falsely claim that …