Not sure if it's possible, but it's certainly not good for the car's transmission, drive train or engine. Whoever did this lap will suffer mightily during races when the damage system is implemented, because this kind of downshifting is very bad for the car.
Having said that, as long as you wait for the revs and speed to drop enough, going from 4th to 2nd is okay. But it's still better for car balance to go 4th-3rd-2nd. Going from 4th-1st isn't optimal, but as long as the minimum speed is low enough, then it can work. But it still places too much strain on the car to use this method over the course of a race to expect to get to the finish line.
I don't usually comment on people's driving and car setup, but sometimes it really irks me. At least his throttle and steering inputs are smooth and consistent. But the way some people downshift really annoys me.
1) His car is geared too long. 5th gear is obsolete.
2) Notice how on the entry to T1, the rear end snapped out? This is because of going from 4th to 1st, results in too much engine braking, and the rear wheels under rotate. Besides, if you've geared your car correctly, you shouldn't need to use 1st at all for a lap of the Nurburgring GP.
3) Probably should have changed up to 3rd on the entry to the final corner as he would have lost some time banging on 2nd gear's rev limiter.
But, in general, he's a good driver in terms of using the gears, and engine braking, and smooth throttle and steering inputs. There are some pretty shocking drivers out there who use WAY too much engine braking, and they don't get penalised for it. I really hope Kunos's damage system will crack down on these people.
Personally I go through all the gears when downshifting. It's more work, yes, but it makes the car more stable and predictable on turn in, not to mention it's kinder on the car's mechanical components.
/Rant over.