A judge has ordered a mental health evaluation for a man charged with shooting his mother after she tried to have him committed for psychiatric care. A police affidavit says 46-year-old Andrew Leighton shot his mother, 68-year-old Shirley Leighton, as she tried to call Spring Harbor Hospital for help. The affidavit says he’d bought the .40-caliber handgun the day before. The victim’s husband, Thomas Leighton, discovered the body Friday night after taking the dog for a walk, and Andrew Leighton was arrested after a standoff. Police say Andrew Leighton had moved in with his parents after a divorce. His lawyer told a judge Monday that his client may be hearing voices. Prosecutors say a competency evaluation will take about 30 days.