The 50% estimated residual value in 5 years is just an estimate and unlikely to hold true unless there's a rapid surge in demand over the next few years. Really, does anyone want to buy a "used test guinea pig?", the first year of all new electric technology? That's like buying a used 2002 E65 7er.

If your friend has a need to be economical, consider a Ford Fiesta, Ford Focus, or VW diesel. They'll hold their value better, be cheap to run, and be loads better to drive.