The Video shows the Mother locking the phone and then unlocking with her face, passes it to her son, Mark who is 10 year old, in less than a second, the phone actually does the same.
According to the Wired, the 10-year-old kid did not just unlocked his mother's phone, but after discovering that he was able to breach phone's security on his mother's phone, he tried hands on another iPhone X, which was of his father, and succeeded there too.
The important part is that when Face ID fails to recognise the user beyond a limited threshold, and the user immediately enters their password, that time the TrueDepth camera takes another photo to improves its reliability. He was even able to unlock his father's iPhone X, but only at one time, but later his was unable to do it. Unlike Touch ID where you can register multiple fingerprints, Face ID is only programmable with one face per device. It was not for this objective that Apple designed and integrated this feature in their latest iPhone X, which is also the USP of this device apart from full screen display and other incredible features.
A short video lock bypass iPhone X appeared on YouTube. Lets take a Look at the Mask! The fifth grader randomly picked one not knowing it was his mother's iPhone X, was taking a look into it and it just got unlocked, which wasn't supposed to happen.
Although family members can be an exception in case of protecting the iPhone X using Face ID, a group of Vietnamese researchers recently claimed that they had fooled the same authentication system using a composite 3D-printed mask. Meanwhile, there's also some "special processing done on the cheeks and around the face" where there are large areas of skin, and the nose is created from silicone. It was also necessary to get a digital scan of the iPhone's owner as well as detailed measurements of their face.
Meanwhile, when the executive Phil Schiller was introducing the iPhone X, he publicly said Apple's engineers had worked with professional mask makers and makeup artists in Hollywood to protect against attempts to beat Face ID.