Joe, after reading what yo added I think I know a bit more of how you feel. I lost my dad long and slow to alcoholism as well. Brilliant man, did some amazing things (in the defense of this country), fell to alcoholism.
It's a tough time Joe and you may have a lot of questions - I did (but you may not
). You do what you can for you, your family, and if you have them, your kids. And do try to look at the good things that happened and make the best of it today. Personaly the best "closure" I think I can do is to be a good (and occasionally cool) dad to my son....
Good luck Joe!