How do you deal with a alcoholic relative?

I don't think lay people like concerned relatives are equipped to help. Alcoholism is a disease (may be diagnosed as "addiction" or "chemical dependency" depending on her behavior) so she will need professional help. And I don't mean BS programs like AA.
AA isn't a "BS program". Its an amazing support system for people who are ready to change.

There isn't help for people unwilling to change. None. They die, or decide to change, ultimately.
there IS help, they don't hafta 'hit bottom' (can die from that).
C # 31 (it includes codependents anonymous, alanon, acoa, etc).
Even AA, u can come till ya wanna 'change' (me, due to court order).
I don't have an answer to this. My mom and grandma are horrible alcoholics. Both just got out of the hospital (they live together) because they couldn't go any further at home, they both have cirrhosis. They're actually doing good this week, so who knows.

I grew up with my mom being a drunk my whole life. It was hard. I experienced a lot of bad things. Things I try to forget.

I'm 28 and have never drinken before. Never will.
I don't think lay people like concerned relatives are equipped to help. Alcoholism is a disease (may be diagnosed as "addiction" or "chemical dependency" depending on her behavior) so she will need professional help. And I don't mean BS programs like AA.
My father was failing in his recovery for +20 years in and out of rehab and pretended to follow AA from time to time. It wasn't until he started taking AA seriously that he got sober. BS or not, AA gave a totally hopeless drunk on his death bed 8 years of sobriety before his cancer illness which gave that drunk 8 years to get to know his children - turns out he was a really nice, kind, and interesting guy.
I come from a family of alcoholics. Aunts, uncles...Mother died from it, dad almost did until he got into the "BS" program at AA (sorry, but thats an absolutely ignorant comment) at age 70 which bought him 20+ years of sobriety until he died a few weeks ago at age 90.

I have five siblings...two of them drink a lot, pretty much daily but are very successful people (doctors and engineer) and at least at this point, I dont know that I would call them alcoholics...yet. Some would. Definitely heavy drinkers, but functional and very doing quite well for themselves.

The younger sister however, is a total loss as is her husband. They had it all, big six figure incomes, huge house in an expensive neighborhood, boats, big dollar cars, fractional ownership of a plane, NFL player friends, you name it they had it. Now they are barely pushing 50 and live in an inlaw's basement and have nothing but one car and some old furniture and a lot of debt. He can barely hold a job anymore and she has some mediocre job as an office assistant or whatever. I dont even talk to her anymore and two of my other siblings dont either. I didnt say a single word to her at my dads funeral. We were as close as can be just before she and her husband started drinking like this. I think I've seen her sober twice in the last decade and when she is, she is sweet as can be. But drunk, she (and her husband) are just....pathetic, manic, absolute jerks. Its 100% of the time now, morning noon or night they are drinking and/or drunk.

They no-showed for a cookout we had for my dad a couple years ago...after calling me and saying they were getting in the car, they had all the stuff they were supposed to bring and were "on their way" there. After two hours, waiting on them since they were bringing some of the essentials for the meal, we were calling and calling, leaving messages and blowing up phones. Nothing. A bit later we finally got a hold of one of their teen kids, who said "Well they've been blaring music and drinking all afternoon out back on the patio, I think mom is asleep and there is no way dad can drive. Are they supposed to be somewhere?" Nope, thanks, talk to you later, click....the next day she said they never, ever committed to being there and they absolutely did not say they were on their way. Classic alcoholic gaslighting and lying.

I have little advice to give as far as how to deal with them, other than stay away. Any money you have, they will try to mooch. Your time, your labor, anything you have they will try to get from you, and they will give you nothing in return but misery. Dont give them money, dont buy them anything, dont drive them to work, dont answer their phone calls, and just avoid them at all costs. Period. You have nothing to gain and everything to lose.
there is a full spectrum of dysfunction from slight to heavy. One statement of what to do will not fit all individuals. If U R one of the 10 "an involved" drags along (dad was a work-a-holic, never home, basically raised fatherless) there are things U can do besides "enable" or"ignore".