TL;DR: At what percent (if any) will alcohol dehydrate you more/faster than drinking nothing?
Let's contrive a situation for dramatic effect...
A human goes out on a boat for a nice sail in the sea. But oh, the sea was angry that day, my friends. The weather turns, and the sailboat is tossed asunder. Luckily, our survivor grabs hold of some debris and is washed onto a deserted island.
Lo and behold, the debris that floated with the survivor to the island is a cooler, and it is filled with beer! There are no other food or water sources on the island. What should our survivor do in regards to the beer to stay alive for as long as possible?
The crux of the situation and my question: will drinking the beer help hydrate the human, keeping them alive longer? Or would the effect of the alcohol as a diuretic actually dehydrate them, causing an earlier demise?
Details and follow up questions: Let's assume this is an average beer ~4% alcohol. However, I know there must be a breaking point. Some kombucha or ginger beer with .5% alcohol should surely be imbibed. But should this beer still be drunk? What if instead it was a 7% IPA? Or a 14% quadruple IPA like I have in my fridge? What about wine, whiskey, or gin?
How would the situation change for a caffeinated beverage like coffee? Or what if the cooler was filled with energy drinks?
I look forward to your answers!
EDIT: The linked question, while similar, does not answer my question. It links to one 1996 study that talks about the effect of alcohol on rehydration, but not the specifics of yes, probably ok to drink at about this percent ABV, and no don't drink at above this percent. It also doesn't discuss rate of intake, changes based on body weight, etc. which are all things I would surmise have an impact on this. I understand there isn't going to be a hard and fast STOP percent level, but I would like to understand more about the underlying mechanisms and factors that change things.