Family Issues Support Group
Family issues is a huge range that go from minor conflict to major misbehaviour and even abuse on the part of individual members of the family occur. Whether you feel you are in a dysfunctional family or you're dealing with a very specific issue, this is the place to talk about it and find others who might be going through the same thing.
As for right now if you are able to find out where he is staying you always have an option to send a letter to him without putting your address on so he might be more likely to open it and express your concerns and feelings. You could also give him the option to possibly at visit his grandma who would really like to see him and visit with him because she is worried and misses him and make arrangements that you or anyone else in the family will not be there if he wishes just to come and say hello to her.
I know you want to see him as well but maybe for now start out slow he might be more apt to at least see his grandma who he knows is elderly and he might be ok in just visiting with her for now. Or you can write a note and see if he will go out for lunch with just you. I know this must be painful but you should also let him know that you will respect whatever decisions he decides to make with his life but you would like to keep in touch from time to time and see how he will respond to that.
I wish I could offer more advice here but without knowing why he left in the first place or how he acted before he left it is hard to determine what his frame of mind is. I do not know if he suffers from mental issues, has drug problems or if he is just dealing with being hurt in the past by his g/f or other people. The best you can do is if you can find where he is at is to send him a note and take it from there.
The only other thing I can think of is get help in tracking him down through friends that he had before he left and see if they might know where he may be. If he is found he still may not want to have contact but it might give you just a little bit of peace of mind to know that he is doing ok. I hope that things can be worked out if you do find him and at the very least you will have some closure. Wishing you the very best:)