What you say about engineering jobs is to some extent true...all skilled engineers are in demand. Computing jobs and other technical specialties are much more heavily impacted by foreign workers. Your grandson may have an additional advantage that Oak Ridge is about 50% government jobs. The federal government cannot make permanent hires of people on H-1B visas. Congrats to your grandson on his achievements and future prospects -- but don't think for a minute that his experience tells the tale for everyone.
That is the job he settled on at Oak Ridge, in part because he had an internship there and liked it. He had several offers and was even offered a spot at MIT to work on his masters. His dad had cancer at the time and he wanted to be closer to home.
In general, I think young people could benefit from technical and trade schools over college in many instances.