Help him define himself by who he is not by who he isn't . It's a tough world. If this was the way they were parented, it may come naturally at first but often changes when they notice the emptiness they bring to fathering. You are the best resource for helping your son learn how to deal with what the world throws at him. Pushing boys as early as possible to act strong and independent usually backfires.
Men have emotions.
Let your son know that a mark of masculinity is recognizing that all humans have limitations and need the support of others. Talk about your experience with the double standard men face in this world. Offer your home, your relationship with him, as respite from the world. The world is going to provide more than enough toughening up. You have expertise in surviving the challenge.