While I think this is often the case--boys having trouble expressing (or experiencing) empathy--I also think that some of the "diagnosis" of this is actually a failure of empathy/understanding towards (some) boys.

For boys who have a strong sense of ego/self-reliance (and some do regardless of culture, though culture can surely shift things somewhat), the kind of squishy oh-they-feel-bad-so-you-should-feel-bad-and-that-is-empathy is not very appealing. Being down hits your ego. Being down hits your self-reliance. Not very appealing!

But the traditional protector mindset works great even for the self-reliant ego-driven individual: it is because you are stable and can take care of yourself that you can offer help to people in need. It doesn't make them into good psychotherapists; doesn't lead them to be a good shoulder to cry on; doesn't mean they're going to constantly attend to little uplifting actions towards other, unprompted. But maybe that wasn't ever really an option for them. If they're on the side of helping others out and taking others' needs seriously, it's still a profoundly pro-social direction to take, where the opposite would be at best callous indifference.

I think this even works okay for people with sociopathic tendencies: they might be physiologically less able to empathize, but they can still perfectly well understand how to adopt a positive pro-social role if there is one on offer. (Most sociopaths are still decent people; they accomplish this in a different way than strongly empathic people, though.)

Making society work for people as-they-are not as-we-hope-they-would-be is very important. We need to take individual difference and individual personality / constitution more seriously than we do.