Touch ID requires your passcode after 48 hours. So, only if the phone had been previously unlocked with a passcode, kept powered on and charged, and 48 hours h

Touch ID requires your passcode after 48 hours. So, only if the phone had been previously unlocked with a passcode, kept powered on and charged, and 48 hours had not elapsed, could the government use a corpse fingerprint to unlock. The device in question is an iPhone 5 and doesn't have a Touch ID sensor, so the question is moot anyway.