https://www.health.harvard.edu/blog/this-is-your-brain-on-alcohol-2017071412000

The body is a funny thing. You don't need to kill a cell directly to cause cellular death, you can, for example, impair cellular fluid replenishment, short circuit repair functions, prevent replication, cause DNA damage that triggers immune responses, etc.

Now, one of the problems with these studies is you can't do brain biopsies on living subjects because of, you know, medical ethics, so it's always possible the shrinkage is a result of fluid loss that just happens to impair memory as well, so the cells are technically alive, but useless.

You very well might be correct that alcohol doesn't directly kill brain cells, but I think you should ask yourself whether being correct on the technicalities is worth more than being correct on the results in this matter.

There simply is not a safe amount of alcohol to consume for brain health.

That's why you should switch to LSD instead.