Alcoholic ketoacidosis is it a quick, painless death for those people?

Fairly: Usually these folks' consciousness is much clouded by the time the metabolic derangements might become uncomfortable. It's treatable nowadays if caught early, but the danger is that someone is binge-drinking alone. I'm sorry if you lost a loved one. There are people who, when they take a drink, cease to be themselves. Remember the good times and go on without asking "what if". Best wishes.