Welcome!
I'm wondering if you've read any literature regarding adult children of alcoholics? It opened my eyes; in fact even mentioning this makes me think I should give the book another read.
If you want a relationship with him, that's great. If you're not ready, that's great, too. The important thing I want you to think about is *BOUNDARIES*. These were a myth to any ACOA growing up - personal space, what's that? haha. If you do choose to visit him, see if you can stay with another family member/friend or rent a hotel room. Tell him that you're only visiting under the guidelines that he will be sober, and if he chooses to drink then you will choose to leave. If you want a relationship with him, do it under YOUR terms.