You will find him at the alien crash site. To get to the site, go to the MDPL-13 power station, and follow the power lines north until you come across the alien distress signal. The signal is called the recon craft Theta signal on your Pip-Boy 3000. You can follow this to the site as it gets louder and clearer as you get closer. The Lone Wanderer's Pip-Boy will indicate higher radiation levels as the player gets closer to the crash site.
The alien cannot be interacted with or looted, but it can be picked up.
Like an object, when you shoot it the pilot doesn't bleed or explode. It is "unbreakable".
Its alien suit is unique, not even on Mothership Zeta will you see a suit like this.
The pilot has some interesting properties when picked up. First, it is weightless, and will sometimes even hover perfectly horizontally. Also, the pilot rotates and flips in a circular pattern when picked up by the head, exactly like the Chinese stealth armor when picked up by the helmet as an item. Also, if you drag it around a bit, its head disappears.