My Dad is drunk tonight, should I still go wish him a Happy Father;s Day

Of course. He deserves love. He may need it now. But not pity and not enabling him ( i.e. don't buy him beer). 
Tell him you love him and get hurt when he drinks. Tell him it upsets you. He may listen and get help for himself. I'm sorry you have to go through this

DON'T be as ignorant as some here giving you bad and wrong advice. YES, by all means, go over and do wish him a Happy Father's Day, and leave a card for him to find tomorrow. You may be one of the few joys he really has in life. Would you honestly be happy if he died never knowing you loved him IN SPITE of his alcoholism? 

NEVER lose an opportunity to tell your mom and your dad that you love them; one day you may never get a chance to do so again. 

Alcoholism is not a choice. It is a disease that does not discriminate on race, ethnic background or national origin, gender or age. It is an ADDICTION, and NO child dreams of growing up to be an alcoholic or homeless or spending time in prisons. 

For unknown reasons, some people are more susceptible than others. There are "triggers" or stressors that precipitate or potentiate the urges, some physical, some psychological and some emotional. 

Do you REALLY, honestly think your father wanted to end up being an alcoholic? And just because he doesn't say anything about it, do you REALLY, HONESTLY think he's proud of being an alcoholic?

No. I cut ties with my dad years ago because of the same thing. I have no regrets. My mother always encouraged me to have a relationship with him even though he was inconsistant with us and verbally abusive towards her. I don't miss him.

Yeah he's your dad. This is his one day to not get judged and disrespected by his own family, make it as special for him as u can.

Tonight might be the best time to with him Happy Father's Day. He's aware of his problem and he needs a bit of love and friendship

Of course. He brought you into this world. Just because he's different right now doesn't mean you should ignore wishing him a happy father's day.

Yeah you should. My dad was an alcoholic. I wished him a happy father's day, and my brother didn't want to. He was mad at him because he was always drinking. Our dad didn't live with us either. I said "he's old though, and I think we should anyway." I did, but he never did....and the next day my dad had a heart attack. I'm not trying to make you feel depressed...but to this day my brother feels awful for not wishing him a happy father's day :( 

I would. If you love him do it.

Okay, here's what you need to do. Go out to the store, get him some aspirin, painkillers, earplugs, and some relaxing music CDs (or find them on YouTube). When he goes to bed, grab his phone and set the date back by one day. Then, when he wakes up, give him the painkillers, aspirin, and relaxing music, and convince him it's Father's Day. Then your gift can be helping him get over his hangover. 

And that's why they say I'm the most gifted of my family.