Dd,
Welcome to SR. Good for you for reaching out and trying to clarify what has happened to you over your short 26 years. First off we do have a forum for adult children of alcoholics. You might try and do some reading there also.
First off you set boundaries with your dad, and they have worked. He wants to continue to drink, and nothing will change that till he is ready. So I hope you all understand that nothing will have changed. In fact alcohlism is progressive, so he could be a lot worse then you know. Your relationship has gotten better because you have not seen the bad side of him in a long time. That bad side will reappear, I guarantee that. It doesn't change, if he is still drinking.
What you and your family have dealt with is tragic. I would highly recommended your siblings and mom to join sr and educate your self about this horrible disease. Your dad is an alcoholic, he doesnt drink to hurt you, he drinks because he is an alcoholic. The more you find out about this disease the more compassion you will have, but I still would not let him back in your home ( in my opinion)
We are here for you, we all understand, because each and everyone of us on this forum, loves an addict. Hugs my friend, keep posting and asking questions. Education is power.