Hi Dalya,
Welcome to this place ---- I'm so sorry for your loss and so sorry you're in pain.
I think that all of us, at one time or another, have thought that there was some magical combination of words we could say that would make an alcoholic seek help.
All of us.
Unfortunately, there just isn't. This really was a choice that your father made, not to seek help, and to keep on drinking. I know that doesn't change the fact that he is not there for you any more, but I see in you the signs of misdirected guilt that we all have here........what should I have done differently? How did I screw up? Why didn't I (insert magic spell here).
Grieve your father's choices, for they're sad ones. But don't blame yourself. There is nothing, nothing, nothing you could've done that would have convinced an active alcoholic to stop drinking against his will.
Hugs to you,
GL