Who to walk me down the aisle?

So this has been stressing me out for sometime. Here is my situation. My father is alive and growing up we were very close. However when I got into high school his drinking started to become a problem. My parents are married but that is a different story. At this point in life he is an alcoholic and because of his actions he has caused a strain in our relationship. I told him a few months back that he wasnt walking me down the aisle unless he gets help. I know with alcoholics you shouldn't give ultimatums, however my dad has had many second chances in life that even almost dying wont lead him to change his ways. So going extreme is the only option. However, he hasnt done anything and I doubt he will.


My dad knows I am a pushover so my sisters, my mom, and fh all are waiting for the day of for me to cave and let him walk me down. Believe me I want him to walk me. But at this point I just cant. He is still invited though.
Now i am just unsure who to have. I dont want to walk by myself. My first pick is my mom, I am worried that will cause some issues though. My fh has offered to walk me, has anyone done that. My other thought is my one grandpa. Just a little confused that is all, but I know whatever decision I make I will be disappointed since it isnt my dad.