FriendWithHope, welcome to SR! You are in the right place to find comfort and support.
Like you, I also struggled greatly with how I could help an alcoholic friend who I cared about and worried about. What I learned is that there is really nothing we as friends can *do* to help. Your friend has to want recovery enough to seek it and follow through with it. It's great that he is starting a program, but it is HIS program to work, and you can't say or do anything that will make him attend the meetings. What you can do is to help *yourself* with your feelings of worry and concern - read and learn all that you can about addiction (whether his is alcohol or another substance). Also please continue to read and post here, it's incredibly helpful.
You can tell your friend that you support him and care about him, but please remember that you cannot cure him. Only he can do that.