This is a bit concerning, if so.
I spent a lot of late nights helping him come up to speed because he's not a bad guy. Even though he probably should have been doing this himself, the fact of the matter is that he chose poorly and now knows a lot about something that is growing less and less valuable every day. You can say that he's not an "engineer" but that's really just the No True Scotsman fallacy talking. It's really hard to compete on the job market when hiring managers just cut out huge swathes of your knowledge a priori, and the fact that happens is what concerns me.
For example, I'm willing to bet that 99% of the most successful iOS developers had not written a line of Objective-C until 3 years ago. Apple simply provided an opportunity and they embraced it, learning the skills they need to adapt.
The guys who are having trouble are the guys who decided that the knowledge they needed for their 9-5 C job was "good enough" so they stopped learning. That's what kills careers.
That's mostly, I think, an argument for moving out of technical backwaters if you're in a technical career. If you let yourself be limited to skills that are more valuable in Minneapolis than the major tech hubs, you're eventually going to be stuck with skills that aren't even valuable in Minneapolis, as the "hot" tech hub technologies become mainstream and finally migrate there way out to the backwaters.