The Water of Life features in lots of fairy tales. Is that what is being referred to?

Likely. Alcohol, in many cultures had a spiritual/religious characterization. We literally have an ancient Egyptian beer recipe because it was written into a hymn praising Ninkasi, a Sumerian goddess of beer.

Is Water of Death another name for an alcohol?

That’s a good question. It’s Fernet (/s).

I do not actually know that. I would suspect that it would be another substance. Maybe an acid or toxin.