Should we simply upload the footage to the internet? Should we contact someone? Could the footage be sold? We are bewildered.

Edit: I am not saying its ghosts, I'm just saying that after watching the videos dozens of times, that we have no explanation.

Here's what happened:

My gf's parents have one of those doorbell cam security systems, that can be linked to an app on your phone. It was being motion activated dozens of times within minutes, and their dogs could be heard going nuts. Her brother, who also has the app on his phone connected to their cameras, called the parents to see what was going on and found that they weren't home, so he decided to go over and investigate. He gets there, pulls up the driveway, parks, and exits the vehicle to go to the front door. He goes into the house, and 10-20 seconds later, his truck drives itself up the driveway, turns, drives between a tree and one of those small solar powered lawn lamps (a little less space than your average car lane between them), and then comes to a stop, fully in their front yard.

Things to note:

1. The driveway is STEEP. Sitting in Drive, no brake applied, you do not move and in fact have to apply the gas to accelerate up the incline. There is zero chance the truck would not roll backward if it was in neutral, and it seems unlikely that it would pull itself forward without giving it gas. Also, if it was a matter of being in the wrong gear, the movement would be instantaneous - Not 10-30 seconds after he has left the vehicle.
2. In the video, you can clearly hear the two times he closes the truck door; when first exiting, and at the end when he gets back in the truck to move it from the yard. No other time is the car door heard
3. At one point in the video, a beam of light from the porch light passes through the cab of the truck, and you can clearly see that there is no one in it.
4. When the truck comes to stop in the yard, the brake lights don't change. The only change seen in the brake lights is when he gets back in his truck to move it from the yard, and you can clearly see the difference as they light up.
5. He said that when he got back in the truck, that it was still in Park.