Now that they have tested it - and by fully discharging and charging the cells several time, which should cell balance the battery pack, see what your battery kappa is now, and what range you are getting.

40 miles range was unrealistically low even for a 14 kWh pack, implying just 2.9 miles/kWh efficiency. I’ve never had anything remotely close to that even under 5F / -15C ambient temperature. With the 16 kWh battery, implied by the test results, your range should be north of 65 miles (EPA range based efficiency, easily beatable in real world).

In my Fiat, I averaged 3 mi/kWh and would really try hard to get past 4 while my father could consistently get over 4.

Well, there are the makings of a practical test - have your father drive the i3 for an hour or so, so the car has a chance to recalibrate the range 'guessometer' to his driving, then fully charge it, and see what range is displayed when the car has 'learned' his driving style.