The blue parachrom hairspring is antimagnetic, but it's not the only part of the watch that can be magnetized. If your BF works around that much magnetism, he should probably just avoid wearing mechanical watches while at work.
With that said, the blue parachrom would definitely help.
Check out these links...
http://www.youtube.com/watch?v=7E3lEiFUmVM
http://www.youtube.com/watch?v=um5WX6WTDhE