I'm fully aware how working in the Internet world for as long as I have has made me unnaturally jaded for my years, so while I have my own personal opinion regarding this video, I don't want to force it upon other people.
Consequently, I'm going to give you two different interpretations and let you pick whichever one floats your boat.
The first is you just saw an old woman experience a genuine roller coaster of emotions after seeing her most prized possession destroyed in a matter of seconds in order to set up a happy ending guaranteed to make everyone feel a little bit better about the world.
The second is the grandmother of a man who makes a living pulling off consistently questionable pranks agreed to star in a video knowing she would probably end up on the receiving end of one because that's his well-established modus operandi.
Either way, grandma got a new car, so I doubt she is going to complain.