Depends. Similar situation as with sociopathy: You can teach a form of “outward empathy” and stress the rational values of empathy and kindness and other values that require a decent ability to relate even if they don’t feel it themselves.
No fear? Depends. Raising a child who feels no fear is likely difficult. But reasoning can be used to teach the rational need of not doing things that should be fearful. Start rational training early and by the age of 7 or so, it should ‘click in’ for the most part…. and then keep at it.