My dad is an alcoholic, i know that it can destroy relationships. He has turned his life around and has been a great father and husband. I am gonna tell you the same thing everyone else has, man up. It will be uncomfortable, it may escalate to him screaming, stay calm and tell him either he sobers up or he cant see your daughter, it's that simple. I have a little sister and if i thought my dad/grandpa was putting her in the slightest danger he wouldn't be allowed near her without me around. Talk to your dad, stand your ground.