They're fairly competitive compared to the rest of the world. He is also working for a US company who could pay him more if they really wanted to. US salaries are high because the US has a glut of engineering jobs and is also a difficult place to immigrate to (generally requires you to have family ties or a job offer which is not easy to obtain when you might not be granted a work visa and won't realistically be able to start for about 6 months). If the US ever adopted a more lax immigration system in line with the UK, Canada, the EU etc I would expect US engineering salaries to drop.