This is not impossible. Maintaining static electricity within one's body for a short period of time is perfectly natural, and IIRC it depends on one's metabolism (i.e. which substances one has in their organism, and in which proportions those are - although these number in most cases differ very slightly between two random persons, this difference matters a lot).
This static electricity "goes off" the moment one touches an object that can act as a conductor; so metal surfaces, wires, some plastics, etc. will do. Paper, feathers and some similar light objects with large surfaces will also work, while, e.g., glass won't.
Putting this much static electricity in yourself as this man does is pretty risky though, and he sure has guts, and knows probably very well what he's doing - I'll give him that.