Triphalangeal Thumb
When an individual has three phalanges on their thumb, this condition is known as a triphalangeal thumb (TPT). The size of the bones may vary, but they result in the thumb appearing similar to the other fingers on the hand.
In this person's case, they must manage with this elongated finger. It is likely, not easy for them to grip objects or maneuver efficiently, but they appear to adapt and cope quite well.
