It depends, professional pilots often botch landings and swear in the cockpit although these landings are still safe (enough) … A landing attempt by a passenge

It depends, professional pilots often botch landings and swear in the cockpit although these landings are still safe (enough) … A landing attempt by a passenger as shown in the YouTube video would probably end with a crash since some manual flying is involved in the end. It is very unlikely that a passenger would getting the controls right at the first time and he (or she) would certainly not be able to perform a go-around. Autoland would be more helpful. In the worst cased, an aircraft can land without flaps and without 'three greens' if the runway is long enough with a high probability of survival for the passengers. Speed control is of course important but the correct speeds for a zero-flap landing could be given from the ground via radio.