I'm so sorry
I don't have children but I can imagine how you must feel. If it's any consolation, I have been away from my mom for 2 years now and I am desperately trying to get closer, I miss her so much. We talk on the phone everyday and have such a close relationship now (I'm 30). I remember being 23 and being so stubborn but the more I was away the more I realized how important being close to my family really is and I'm sure your son will too.
Hugs to you~