Self identityHow will Gene's ability affect him in life?
I'm not exactly sure what your question means. If you're asking about Gene's literal abilities--his athleticism, his intellect--I'm sure they will help him be successful in life, as those are abilities society seems to value. If you mean something else, which I suspect you do but have no idea how to guess it, please re-post with something which will get you better input. We're here to help but need a little more guidance from you.
Gene's introspection, which is clearly growing on him as the action of the story unfolds, will eventually couple with his natural intellectual talents to make him a sympathetic person. He may yearn to be sentimental and for the innocence sentimentality implies, but this is closed to him because he understands that even in the youth he remembers, innocence was no protection against mistakes and enmity.
Gene's ability to evaluate his past conduct and motives objectively, recognizing that both private and world wars are made "by something ignorant in the human heart," will serve him well in the future. For, Gene will consider what his personal intentions are before he acts.