Cool place to be; I have spent a lot of time accross the street in the old B-52 hangar for flight test operations. There is a lot of not just Boeing, but aviation history at this site. He will have a great time, and learn a good deal. Good for him. Oh, and my mom works in the 2-122 building, but she is retiring in May.
The 2-122 building is the one just south of the little inlet off the Duwamish in the photo below, with 12th Avenue South right in front of it to the east. The old B-52 hangar is the large building northeast, accross East Marginal Way.
View Larger Map
Anyway, as far as places to live, the guys above are right on. This isn't the greatest part of town for anyone to live in, particularly a young man far from home. There certainly are nicer neighborhoods well within a short bus ride, though, as mentioned above. I'll second everyone on the "stay-out" zones, though. Pretty damn rough neighborhoods.
Edit - I don't know why my "zoomed in" version of the map won't open. Just "view larger map" and zoom in on the plant. You'll see two little inlets off the Duwamish River - the southernmost one, near 12th Avenuse South, is the one adjoining the 2-122 building, which is right on the south side of it.